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In-Press Preview

Articles in this category appear as authors submitted them for publication, prior to copyediting and publication layout.
CCL5 mediates CD40-driven CD4+ T-cell tumor infiltration and immunity
The role CD4+ T-cells play in tumor immunity is less well-appreciated than the cytotoxic role of CD8+ T-cells. Despite clear evidence for CD4+ T-cell dependency across multiple immunotherapies, the...
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Research In-Press Preview Immunology Oncology

CCL5 mediates CD40-driven CD4+ T-cell tumor infiltration and immunity

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The role CD4+ T-cells play in tumor immunity is less well-appreciated than the cytotoxic role of CD8+ T-cells. Despite clear evidence for CD4+ T-cell dependency across multiple immunotherapies, the mechanisms by which CD4+ T-cells infiltrate tumors remain poorly understood. Prior studies by our group have shown in a mouse model of pancreatic cancer that systemic activation of the cell-surface TNF superfamily member CD40 drives T-cell infiltration into tumors and in combination with immune checkpoint blockade, leads to durable tumor regressions and cures that depend on both CD8+ and CD4+ T-cells. Here, we used single-cell transcriptomics to examine the tumor microenvironment following treatment with agonist CD40 antibody with or without immune checkpoint blockade. We show that intratumoral myeloid cells produce the chemokine CCL5 in response to CD40 agonist and that CCL5 mediates an influx of CD4+ T-cells into the tumor microenvironment. Disruption of CCL5 genetically or pharmacologically mitigates the influx of CD4+ but not CD8+ T-cells into tumors and blunts the therapeutic efficacy of immunotherapy. These findings highlight a previously unappreciated role for CCL5 in selectively mediating CD4+ T-cell tumor infiltration in response to effective immunotherapy.

Authors

Austin P. Huffman, Jeffrey H. Lin, Samuel I. Kim, Katelyn T. Byrne, Robert H. Vonderheide

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The laboratory tests and host immunity of COVID-19 patients with different severity of illness
Background: The Coronavirus Disease-2019 (COVID-19), infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a severe outbreak in China. The host immunity of COVID-19...
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Clinical Research and Public Health In-Press Preview COVID-19 Immunology Infectious disease

The laboratory tests and host immunity of COVID-19 patients with different severity of illness

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Background: The Coronavirus Disease-2019 (COVID-19), infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a severe outbreak in China. The host immunity of COVID-19 patients is unknown. Methods: The routine laboratory tests and host immunity in COVID-19 patients with different severity of illness were compared after patient admission. Results: A total of 65 SARS-CoV-2-positive patients were classified as mild (n=30), severe (n=20), and extremely severe (n=15) illness. Many routine laboratory tests such as ferritin, lactate dehydrogenase and D-dimer were increased in severe and extremely severe patients. The absolute numbers of CD4+ T cells, CD8+ T cells and B cells were all gradually decreased with increased severity of illness. The activation markers such as HLA-DR and CD45RO expressed on CD4+ and CD8+ T cells were increased in severe and extremely severe patients compared with mild patients. The co-stimulatory molecule CD28 had opposite results. The percentage of natural regulatory T cells was decreased in extremely severe patients. The percentage of IFN-γ producing CD8+ T cells was increased in both severe and extremely severe patients compared with mild patients. The percentage of IFN-γ producing CD4+ T cells was increased in extremely severe patients. The IL-2R, IL-6, and IL-10 were all increased in extremely severe patients. The activation of DC and B cells was decreased in extremely severe patients. Conclusions: The number and function of T cells are inconsistent in COVID-19 patients. The hyperfunction of CD4+ and CD8+ T cells is associated with the pathogenesis of extremely severe SARS-CoV-2 infection.

Authors

Feng Wang, Hongyan Hou, Ying Luo, Guoxing Tang, Shiji Wu, Min Huang, Weiyong Liu, Yaowu Zhu, Qun Lin, Liyan Mao, Minghao Fang, Huilan Zhang, Ziyong Sun

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Upregulation of BDNF and hippocampal functions by a hippocampal ligand of PPARα
Discovery strategies commonly focus on the identification of chemical libraries or natural products, but the modulation of endogenous ligands offers a much better therapeutic strategy due to their...
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Research In-Press Preview Neuroscience

Upregulation of BDNF and hippocampal functions by a hippocampal ligand of PPARα

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Discovery strategies commonly focus on the identification of chemical libraries or natural products, but the modulation of endogenous ligands offers a much better therapeutic strategy due to their low adverse potential. Recently, we have seen that hexadecanamide (Hex) is present in hippocampal nuclei of normal mice as an endogenous ligand of peroxisome proliferator-activated receptor alpha (PPARα). This study underlines the importance of Hex in inducing the expression of brain-derived neurotrophic factor (BDNF) from hippocampal neurons via PPARα. The level of Hex was less in the hippocampus of 5xFAD mice as compared to non-Tg mice. Oral administration of Hex increased the level of this molecule in the hippocampus to stimulate BDNF and its downstream plasticity-associated molecules, promote synaptic functions in the hippocampus and improve memory and learning in 5xFAD mice. However, oral Hex remained unable to stimulate hippocampal plasticity and improve cognitive behaviors in 5xFADPparα-null (5x with global PPARα-/-) and 5xFADPparα-ΔHippo (5x with hippocampus-specific PPARα-/-) mice, indicating an essential role of hippocampal PPARα in Hex-mediated improvement in hippocampal functions. This is the first demonstration of protection of hippocampal functions by oral administration of a hippocampus-based drug, suggesting that hexadecanamide may be explored for therapeutic intervention in AD.

Authors

Dhruv R. Patel, Avik Roy, Sumita Raha, Madhuchhanda Kundu, Frank Gonzalez, Kalipada Pahan

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Protein Kinase G1 regulates bone regeneration and rescues diabetic fracture healing
Bone fractures are a major cause of morbidity and mortality, particularly in diabetic patients, who have a high incidence of fractures and exhibit poor fracture healing. Coordinated expression of...
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Research In-Press Preview Bone biology

Protein Kinase G1 regulates bone regeneration and rescues diabetic fracture healing

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Bone fractures are a major cause of morbidity and mortality, particularly in diabetic patients, who have a high incidence of fractures and exhibit poor fracture healing. Coordinated expression of osteoblast-derived vascular endothelial growth factor (VEGF) and bone morphogenic proteins (BMPs) is essential for fracture repair. The NO/cGMP/protein kinase G (PKG) signaling pathway mediates osteoblast responses to estrogens and mechanical stimulation, but the pathway’s role in bone regeneration is unknown. Here, we used a mouse cortical defect model to simulate bone fractures and studied osteoblast-specific PKG1 knockout and diabetic mice. The knock-out mice had normal bone micro-architecture, but after injury exhibited poor bone regeneration, with decreased osteoblasts, collagen deposition, and microvessels in the bone defect area. Primary osteoblasts and tibiae from the knock-out mice expressed low amounts of Vegfa and Bmp2/4 mRNAs, and PKG1 was required for cGMP-stimulated expression of these genes. Diabetic mice also demonstrated low Vegfa and Bmp2/4 expression in bone and impaired bone regeneration after injury; notably, the cGMP-elevating agent cinaciguat restored Vegfa and BMP2/4 expression, and full bone healing. We conclude that PKG1 is a key orchestrator of VEGF and BMP signaling during bone regeneration and propose pharmacological PKG activation as a novel therapeutic approach to enhance fracture healing.

Authors

Nadine Schall, Julian J. Garcia, Hema Kalyanaraman, Shyamsundar Pal China, Jenna J. Lee, Robert L. Sah, Alexander Pfeifer, Renate B. Pilz

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Age-dependent regulation of cell-mediated collagen turnover
Although aging represents the most important epidemiologic risk factor for fibrotic disease, the reasons for this are incompletely understood. Excess collagen deposition in tissues is the sine qua...
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Research In-Press Preview Aging Pulmonology

Age-dependent regulation of cell-mediated collagen turnover

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Although aging represents the most important epidemiologic risk factor for fibrotic disease, the reasons for this are incompletely understood. Excess collagen deposition in tissues is the sine qua non of tissue fibrosis and can be viewed as an imbalance between collagen production and collagen degradation. Yet we still lack a detailed understanding of the changes that take place during development, maturation and aging in extracellular-matrix (ECM) dynamics. Resolution of fibrosis is impaired in aging and this impairment may explain why age is the most important risk factor for fibrotic diseases such as Idiopathic Pulmonary Fibrosis. However, ECM dynamics and impaired resolution of fibrosis in aging remain understudied. Here we show that cell-mediated collagen uptake and degradation are diminished in aged animals and this finding correlates with downregulation of the collagen endocytic receptor Mrc2. We identify Myeloid Zinc Finger-1 as a novel transcriptional regulator of Mrc2 and both this transcription factor and Mrc2 are downregulated in multiple tissues and organisms in an age-dependent manner. Thus, cell-mediated degradation of collagen is an essential process that promotes resolution of fibrosis and impairment in this process contributes to age-related fibrosis.

Authors

Michael J. Podolsky, Christopher D. Yang, Carlos Lizama, Ritwik Datta, Steven K. Huang, Stephen L. Nishimura, Sarah L. Dallas, Paul Wolters, Claude Jourdan Le Saux, Kamran Atabai

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Myocyte-derived Myomaker expression is required for regenerative fusion but exacerbates membrane instability in dystrophic myofibers
Muscle progenitor cell fusion is required for the formation and regeneration of multinucleated skeletal muscle fibers. Chronic muscle regeneration in Duchenne muscular dystrophy (DMD) is...
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Research In-Press Preview Muscle biology Stem cells

Myocyte-derived Myomaker expression is required for regenerative fusion but exacerbates membrane instability in dystrophic myofibers

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Muscle progenitor cell fusion is required for the formation and regeneration of multinucleated skeletal muscle fibers. Chronic muscle regeneration in Duchenne muscular dystrophy (DMD) is characterized by ongoing fusion of satellite cell (SC) progeny, but the effects of fusion on disease and the mechanisms by which fusion is accomplished in this setting are not fully understood. Using the mdx mouse model of DMD, we deleted the fusogenic protein Myomaker in SCs or myofibers. Following deletion in SCs, mice displayed a complete lack of myocyte fusion, resulting in severe muscle loss, enhanced fibrosis, and significant functional decline. Reduction of Myomaker in mature myofibers in mdx mice, however, led to minimal alterations in fusion dynamics. Unexpectedly, myofiber-specific deletion of myomaker resulted in improvement of disease phenotype, with enhanced function and decreased muscle damage. Our data indicate that Myomaker has divergent effects on dystrophic disease severity depending upon its compartment of expression. These findings show that myocyte fusion is absolutely required for effective regeneration in DMD, but persistent Myomaker expression in myofibers due to ongoing fusion may have unintended deleterious consequences for muscle integrity. Thus, sustained activation of a component of the myogenic program in dystrophic myofibers exacerbates disease.

Authors

Michael J. Petrany, Taejeong Song, Sakthivel Sadayappan, Douglas P. Millay

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COVID-19 in older adults: clinical, psychosocial, and public health considerations
Complications of COVID-19 have been particularly severe among older adults, who are the focus of this article. Public policy goals should prioritize pandemic preparedness in nursing homes, as well...
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Viewpoint In-Press Preview COVID-19

COVID-19 in older adults: clinical, psychosocial, and public health considerations

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Complications of COVID-19 have been particularly severe among older adults, who are the focus of this article. Public policy goals should prioritize pandemic preparedness in nursing homes, as well as civic and local government-based support programs for community-dwelling older adults, to ensure that risk of infection is mitigated while promoting wellness during a period of stress and uncertainty.

Authors

John P. Mills, Keith S. Kaye, Lona Mody

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A human-origin probiotic cocktail ameliorates aging-related leaky gut and inflammation via modulating microbiota-taurine-tight junction axis
Inflammation is a major risk factor of morbidity and mortality in older adults. Although its precise etiology is unknown, low-grade inflammation in older adults is commonly associated with...
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Research In-Press Preview Gastroenterology Microbiology

A human-origin probiotic cocktail ameliorates aging-related leaky gut and inflammation via modulating microbiota-taurine-tight junction axis

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Inflammation is a major risk factor of morbidity and mortality in older adults. Although its precise etiology is unknown, low-grade inflammation in older adults is commonly associated with increased intestinal epithelial permeability (leaky gut) and abnormal (dysbiotic) gut microbiota. The increasing older population and lack of treatments to reduce aging-related microbiota dysbiosis, leaky gut and inflammation culminates on a rise in aging-related comorbidities, constituting a significant public health concern. Here we demonstrate that a human-origin probiotic cocktail containing 5-Lactobacillus and 5 Enterococcus strains isolated from healthy infant’s gut prevents high-fat diet (HFD)-induced microbiota dysbiosis, leaky gut, inflammation, metabolic dysfunctions and physical function decline in older mice. Probiotic-modulated gut microbiota primarily reduced leaky gut by increasing tight junctions, which in turn reduced inflammation. Mechanistically, probiotics modulated microbiota in a way to increases bile salt hydrolase activity, which in turn increased taurine abundance in the gut that stimulated tight junctions and suppressed gut leakiness. Further, in Caenorhabditis elegans, taurine increased life span, reduced adiposity and leaky gut, and enhanced physical function. The results suggest that such probiotic therapies could prevent or treat aging-related leaky gut and inflammation in elderly.

Authors

Shokouh Ahmadi, Shaohua Wang, Ravinder Nagpal, Bo Wang, Shalini Jain, Atefeh Razazan, Sidharth P. Mishra, Xuewei Zhu, Zhan Wang, Kylie Kavanagh, Hariom Yadav

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Formation of colorectal liver metastases induces musculoskeletal and metabolic abnormalities consistent with exacerbated cachexia
Advanced colorectal cancer (CRC) is often accompanied by development of liver metastases (LMs) and skeletal muscle (SkM) wasting, i.e. cachexia. Despite plaguing the majority of CRC patients,...
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Research In-Press Preview Cell biology Muscle biology

Formation of colorectal liver metastases induces musculoskeletal and metabolic abnormalities consistent with exacerbated cachexia

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Advanced colorectal cancer (CRC) is often accompanied by development of liver metastases (LMs) and skeletal muscle (SkM) wasting, i.e. cachexia. Despite plaguing the majority of CRC patients, cachexia remains unresolved. By using mice subcutaneously (C26) or intrasplenically injected with C26 tumor cells to mimic hepatic dissemination of cancer cells (mC26), here we aimed to further characterize functional, molecular and metabolic effects on SkM and examine whether LMs exacerbate CRC-induced cachexia. C26-derived LMs were associated with progressive loss of body weight, as well as with significant reductions in SkM size and strength, in line with reduced phosphorylation of markers of protein anabolism and enhanced protein catabolism. mC26 hosts showed prevalence of fibers with glycolytic metabolism and enhanced lipid accumulation, consistent with abnormalities of mitochondrial homeostasis and energy metabolism. In a comparison with mice bearing subcutaneous C26, cachexia appeared exacerbated in the mC26 hosts, as also supported by differentially expressed pathways within SkM. Overall, our model recapitulates the cachectic phenotype of metastatic CRC and reveals that formation of LMs resulting from CRC exacerbate cancer-induced SkM wasting by promoting differential gene expression signatures.

Authors

Joshua R. Huot, Leah J. Novinger, Fabrizio Pin, Ashok Narasimhan, Teresa A. Zimmers, Thomas M. O'Connell, Andrea Bonetto

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Gut microbial metabolites alter IgA immunity in type 1 diabetes
The incidence of type 1 diabetes (T1D) has been increasing among children and adolescents, which environmental factors including gut microbiota play an important role. However, the underlying...
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Research In-Press Preview

Gut microbial metabolites alter IgA immunity in type 1 diabetes

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The incidence of type 1 diabetes (T1D) has been increasing among children and adolescents, which environmental factors including gut microbiota play an important role. However, the underlying mechanisms are yet to be determined. Here, we show that patients with newly diagnosed T1D displayed not only a distinct profile of gut microbiota associated with decreased short-chain fatty acid (SCFAs) production, but also an altered IgA-mediated immunity compared with healthy control subjects. Using germ free (GF) non-obese diabetic (NOD) mice, we demonstrate that gut microbiota from patients with T1D promoted different IgA-mediated immune responses compared with healthy control gut microbiota. Treatment with the SCFA, acetate, reduced gut bacteria-induced IgA response accompanied by decreased severity of insulitis in NOD mice. Our study provides new insights into the functional effects of gut microbiota on inducing IgA immune response in T1D, suggesting that SCFAs might be potential therapeutic agents in T1D prevention and/or treatment.

Authors

Juan Huang, James A. Pearson, Jian Peng, Youjia Hu, Sha Sha, Yanpeng Xing, Gan Huang, Xia Li, Fang Hu, Zhiguo Xie, Yang Xiao, Shuoming Luo, Chen Chao, Florence S. Wong, Zhiguang Zhou, Li Wen

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Photoacoustic imaging of kidney fibrosis for assessing pre-transplant organ quality
Roughly 10% of the world’s population has chronic kidney disease (CKD). In its advanced stages, CKD greatly increases the risk of hospitalization and death. Although kidney transplantation has...
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Resource and Technical Advance In-Press Preview Nephrology

Photoacoustic imaging of kidney fibrosis for assessing pre-transplant organ quality

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Roughly 10% of the world’s population has chronic kidney disease (CKD). In its advanced stages, CKD greatly increases the risk of hospitalization and death. Although kidney transplantation has revolutionized the care of advanced CKD, clinicians have limited ways of assessing donor kidney quality. Thus, optimal donor kidney-recipient matching can not be performed, meaning that some patients receive damaged kidneys that function poorly. Fibrosis is a form of chronic damage often present in donor kidneys that is an important predictor of future renal function. Currently, no safe, easy to perform technique exists that accurately quantifies renal fibrosis. We describe a novel photoacoustic (PA) imaging technique that directly images collagen, the principal component of fibrotic tissue. PA imaging non-invasively quantifies whole kidney fibrotic burden in mice, and cortical fibrosis in pig and human kidneys, with outstanding accuracy and speed. Remarkably, three-dimensional PA imaging exhibited sufficiently high resolution to capture intra-renal variations in collagen content. We further show that PA imaging can be performed in a setting that mimics human kidney transplantation, suggesting the potential for rapid clinical translation. Taken together, our data suggests that PA collagen imaging is a major advance in fibrosis quantification that could have widespread pre-clinical and clinical impact.

Authors

Eno Hysi, Xiaolin He, Muhannad N. Fadhel, Tianzhou Zhang, Adriana Krizova, Michael Ordon, Monica Farcas, Kenneth T. Pace, Victoria Mintsopoulos, Warren L. Lee, Michael Kolios, Darren Yuen

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In vivo directed evolution of AAV in the primate retina
Efficient AAV-mediated gene delivery remains a significant obstacle to effective retinal gene therapies. Here, we apply directed evolution - guided by deep sequencing and followed by direct in vivo...
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Research In-Press Preview Ophthalmology

In vivo directed evolution of AAV in the primate retina

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Efficient AAV-mediated gene delivery remains a significant obstacle to effective retinal gene therapies. Here, we apply directed evolution - guided by deep sequencing and followed by direct in vivo secondary selection of high-performing vectors with a GFP-barcoded library - to create AAV viral capsids with new capabilities to deliver genes to the outer retina in primates. A replication incompetent library, produced via providing rep in trans, was created to mitigate risk of AAV propagation. Six rounds of in vivo selection with this library in primates, involving intravitreal library administration, recovery of genomes from outer retina, and extensive next generation sequencing of each round, resulted in vectors with redirected tropism to the outer retina and increased gene delivery efficiency to retinal cells. These new viral vectors expand the toolbox of vectors available for primate retina, and may enable less invasive delivery of therapeutic genes to patients, potentially offering retina-wide infection at a similar dosage to vectors currently in clinical use.

Authors

Leah C. Byrne, Timothy P. Day, Meike Visel, Cécile Fortuny, Deniz Dalkara, William H. Merigan, David V. Schaffer, John G. Flannery

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Accelerated osteocyte senescence and skeletal fragility in mice with type 2 diabetes
The worldwide prevalence of type 2 diabetes (T2D) is increasing. Despite normal to higher bone density, patients with T2D paradoxically have elevated fracture risk resulting, in part, from poor...
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Research In-Press Preview Bone biology

Accelerated osteocyte senescence and skeletal fragility in mice with type 2 diabetes

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The worldwide prevalence of type 2 diabetes (T2D) is increasing. Despite normal to higher bone density, patients with T2D paradoxically have elevated fracture risk resulting, in part, from poor bone quality. Advanced glycation endproducts (AGEs) and inflammation as a consequence of enhanced receptor for AGE (RAGE) signaling are hypothesized culprits, although the exact mechanisms underlying skeletal dysfunction in T2D are unclear. Lack of inducible models that permit environmental (in obesity) and temporal (after skeletal maturity) control of T2D onset has hampered progress. Here, we show in C57BL/6 mice that a one-time pharmacological intervention (streptozotocin [STZ]) initiated in adulthood combined with high-fat diet (HFD)-induced obesity caused hallmark features of human adult-onset T2D, including prolonged hyperglycemia, insulin resistance, and pancreatic β-cell dysfunction, but not complete destruction. In addition, HFD/STZ (i.e., T2D) resulted in several changes in bone quality that closely mirror those observed in humans, including compromised bone microarchitecture, reduced biomechanical strength, impaired bone material properties, altered bone turnover, and elevated levels of the AGE, CML, in bone and blood. Furthermore, T2D led to the premature accumulation of senescent osteocytes with a unique pro-inflammatory signature. These findings highlight the RAGE pathway and senescent cells as potential targets to treat diabetic skeletal fragility.

Authors

Brittany A. Eckhardt, Jennifer L. Rowsey, Brianne S. Thicke, Daniel G. Fraser, Katherine L. O’Grady, Olga P. Bondar, Jolaine M. Hines, Ravinder J. Singh, Andrew R. Thoreson, Kuntol Rakshit, Anthony B. Lagnado, João F. Passos, Adrian Vella, Aleksey V. Matveyenko, Sundeep Khosla, David G. Monroe, Joshua N. Farr

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Altered calcium-handling produces reentry-promoting action potential alternans in atrial fibrillation-remodeled hearts
Atrial fibrillation (AF) alters atrial-cardiomyocyte (ACM) Ca2+-handling, promoting ectopic-beat formation. Here, we examined the effects of AF-associated remodeling on Ca2+-related...
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Research In-Press Preview Cardiology

Altered calcium-handling produces reentry-promoting action potential alternans in atrial fibrillation-remodeled hearts

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Atrial fibrillation (AF) alters atrial-cardiomyocyte (ACM) Ca2+-handling, promoting ectopic-beat formation. Here, we examined the effects of AF-associated remodeling on Ca2+-related action-potential (AP) dynamics and consequences for AF-susceptibility. AF was maintained electrically (x1 week) in dogs by right-atrial (RA) tachypacing. ACMs isolated from AF-dogs showed increased Ca2+-release refractoriness, spontaneous Ca2+-spark frequency and cycle-length (CL) threshold for Ca2+ and APD alternans versus controls. Similarly, AF increased the in-situ CL-threshold for Ca2+/APD-alternans and spatial dispersion in Ca2+-release recovery kinetics, leading to spatially-discordant alternans associated with reentrant rotor formation and susceptibility to AF induction/maintenance. The clinically-available agent dantrolene reduced Ca2+-leak and CL-threshold for Ca2+/APD-alternans in both ACMs and AF-dog RA, while suppressing AF-susceptibility; caffeine increased Ca2+-leak, CL-threshold for Ca2+/APD-alternans in control-dog ACMs and RA-tissues. In vivo, the atrial repolarization alternans CL-threshold was increased in AF vs control, as was AF-vulnerability. Intravenous dantrolene restored repolarization alternans-threshold and reduced AF-vulnerability. Immunoblots showed significantly reduced expression of total and phosphorylated ryanodine-receptors and calsequestrin in AF, along with unchanged phospholamban/SERCA expression. Thus, in addition to promoting spontaneous ectopy, AF-induced Ca2+-handling abnormalities favor AF-occurrence by enhancing vulnerability to repolarization-alternans, thereby promoting the initiation and maintenance of reentrant activity; the clinically-available compound dantrolene provides a lead-molecule to target this mechanism.

Authors

Tao Liu, Feng Xiong, Xiao-yan Qi, Jiening Xiao, Louis Villeneuve, Issam Abu-Taha, Dobromir Dobrev, Congxin Huang, Stanley Nattel

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Intercalated cell BKα subunit is required for flow-induced K+ secretion
BK channels are expressed in intercalated (ICs) and principal (PCs) cells in the cortical collecting duct (CCD) of the mammalian kidney and have been proposed to be responsible for flow-induced K+...
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Research In-Press Preview Cell biology Nephrology

Intercalated cell BKα subunit is required for flow-induced K+ secretion

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BK channels are expressed in intercalated (ICs) and principal (PCs) cells in the cortical collecting duct (CCD) of the mammalian kidney and have been proposed to be responsible for flow-induced K+ secretion (FIKS) and K+ adaptation. To examine the IC-specific role of BK channels, we generated a mouse with targeted disruption of the pore-forming BK alpha subunit (BKα) in ICs (IC-BKα-KO). Whole cell charybdotoxin (ChTX)-sensitive K+ currents were readily detected in control ICs, but largely absent in ICs of IC-BKα-KO mice. When placed on a high K+ (HK) diet for 13 days, blood [K+] was significantly greater in IC-BKα-KO mice vs. controls in males only, although urinary K+ excretion rates following isotonic volume expansion were similar in males and females. FIKS was present in microperfused CCDs isolated from controls, but was absent in IC-BKα-KO CCDs of both sexes. Also, flow-stimulated ENaC-mediated Na+ absorption was greater in CCDs from female IC-BKα-KO mice than in CCDs from males. Our results confirm a critical role of IC BK channels in FIKS. Sex contributes to the capacity for adaptation to a HK diet in IC-BKα-KO mice.

Authors

Rolando Carrisoza-Gaytan, Evan C. Ray, Daniel Flores, Allison L. Marciszyn, Peng Wu, Leah Liu, Arohan R. Subramanya, WenHui Wang, Shaohu Sheng, Lubika J. Nkashama, Jingxin Chen, Edwin K. Jackson, Stephanie M. Mutchler, Szilvia Heja, Donald E. Kohan, Lisa M. Satlin, Thomas R. Kleyman

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Metabolic reprogramming augments potency of human pSTAT3-inhibited iTregs to suppress alloreactivity
Immune suppressive donor regulatory T cells (Tregs) can prevent graft-versus-host disease (GVHD) or solid organ allograft rejection. We previously demonstrated inhibiting STAT3 phosphorylation...
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Research In-Press Preview Immunology Transplantation

Metabolic reprogramming augments potency of human pSTAT3-inhibited iTregs to suppress alloreactivity

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Immune suppressive donor regulatory T cells (Tregs) can prevent graft-versus-host disease (GVHD) or solid organ allograft rejection. We previously demonstrated inhibiting STAT3 phosphorylation (pSTAT3) augments FOXP3 expression, stabilizing induced Tregs (iTregs). Here we report human pSTAT3-inhibited iTregs prevent human skin graft rejection and xenogeneic GVHD yet spare donor anti-leukemia immunity. pSTAT3-inhibited iTregs express increased levels of skin-homing CLA antigen, immune suppressive GARP and PD-1, and IL-9 that supports tolerizing mast cells. Further, pSTAT3-inhibited iTregs significantly reduce alloreactive conventional T cells, Th1, and Th17 cells implicated in GVHD and tissue rejection, and impair infiltration by pathogenic Th2 cells. Mechanistically, pSTAT3 inhibition of iTregs provokes a shift in metabolism from oxidative phosphorylation (OxPhos) to glycolysis and reduced electron transport chain activity. Strikingly, co-treatment with coenzyme Q10 (coQ10) restores OxPhos in pSTAT3-inhibited iTregs and augments their suppressive potency. These findings support the rationale for clinically testing the safety and efficacy of metabolically tuned, human pSTAT3-inhibited iTregs to control alloreactive T cells.

Authors

Kelly Walton, Mario R. Fernandez, Elizabeth M. Sagatys, Jordan Reff, Jongphil Kim, Marie Catherine Lee, John Kiluk, Jane Yuet Ching Hui, David McKenna, Meghan Hupp, Colleen Forster, Michael A. Linden, Nicholas J. Lawrence, Harshani R. Lawrence, Joseph Pidala, Steven Z. Pavletic, Bruce R. Blazar, Said M. Sebti, John L. Cleveland, Claudio Anasetti, Brian C. Betts

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A role for TNFalpha in alveolar macrophage damange-associated molecular pattern release
Chronic beryllium disease (CBD) is a metal hypersensitivity/autoimmune disease in which damage-associated molecular patterns (DAMPs) promote a break in T cell tolerance and expansion of...
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Research In-Press Preview Immunology

A role for TNFalpha in alveolar macrophage damange-associated molecular pattern release

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Chronic beryllium disease (CBD) is a metal hypersensitivity/autoimmune disease in which damage-associated molecular patterns (DAMPs) promote a break in T cell tolerance and expansion of Be2+/self-peptide reactive CD4+ T cells. In this study, we investigated the mechanism of cell death induced by beryllium particles (Be) in alveolar macrophages (AMΦs) and its impact on DAMP release. We found that phagocytosis of Be led to AM cell death independently of caspase, RIP1K, RIP3K or ROS activity. Prior to cell death, Be-exposed AMΦs secreted TNFalpha that boosted intracellular stores of IL-1alpha followed by caspase 8-dependent fragmentation of DNA. IL-1alpha and nucleosomal DNA were subsequently released from AMΦs upon loss of plasma membrane integrity. In contrast, necrotic AMs released only unfragmented DNA and necroptotic AMΦs released only IL-1alpha. In mice exposed to Be, TNFalpha promoted release of both DAMPs and was required for the mobilization of immunogenic DCs, expansion of Be-reactive CD4+ T cells and pulmonary inflammation in a mouse model of CBD. Thus, early autocrine effects of particle-induced TNFalpha on AMs led to a break in peripheral tolerance. This novel mechanism may underlie the known relationship between fine particle inhalation, TNFalpha and loss of peripheral tolerance in T cell-mediated autoimmune disease and hypersensitivities.

Authors

Morgan K. Collins, Abigail M. Shotland, Morgan F. Wade, Shaikh M. Atif, Denay J.K. Richards, Manolo Torres-Llompart, Douglas G. Mack, Allison K. Martin, Andrew P. Fontenot, Amy S. McKee

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CX3CR1-CD8+ T cells are critical in antitumor efficacy, but functionally suppressed in the tumor microenvironment
While blockade of PD-1/PD-L1 immune checkpoint revolutionized cancer treatment, how it works on tumor-infiltrating CD8+ T cells recognizing the same antigen at various differentiation stages...
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Research In-Press Preview Immunology

CX3CR1-CD8+ T cells are critical in antitumor efficacy, but functionally suppressed in the tumor microenvironment

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Abstract

While blockade of PD-1/PD-L1 immune checkpoint revolutionized cancer treatment, how it works on tumor-infiltrating CD8+ T cells recognizing the same antigen at various differentiation stages remains elusive. Here, we found that the chemokine receptor CX3CR1 identified three distinct differentiation states of intratumoral CD8+ T-cell subsets. Adoptively transferred antigen-specific CX3CR1neg CD8+ T cells generated phenotypically and functionally distinct CX3CR1int and CX3CR1hi subsets in the periphery. Notably, expression of co-inhibitory receptors and Tcf1 inversely correlated with the degree of T-cell differentiation defined by CX3CR1. Despite significantly lower expression of co-inhibitory receptors and potent cytolytic activity, in vivo depletion of the CX3CR1hi subset did not alter the antitumor efficacy of adoptively transferred CD8+ T cells. Furthermore, differentiated CX3CR1int and CX3CR1hi subsets were impaired in their ability to undergo proliferation upon re-stimulation, and had no impact on established tumors upon second adoptive transfer compared with the CX3CR1neg subset that remained effective. Accordingly, anti-PD-L1 therapy preferentially rescued proliferation and cytokine production of the CX3CR1neg subset, and significantly enhanced antitumor efficacy of adoptively transferred CD8+ T cells. These findings provide a better understanding of the phenotypic and functional heterogeneity of tumor-infiltrating CD8+ T cells, and can be exploited to develop more effective immunotherapy.

Authors

Takayoshi Yamauchi, Toshifumi Hoki, Takaaki Oba, Hidehito Saito, Kristopher Attwood, Michael S. Sabel, Alfred E. Chang, Kunle Odunsi, Fumito Ito

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Prehospital plasma is associated with distinct biomarker expression following injury
Background: Prehospital plasma improves survival in severely injured trauma patients at risk for hemorrhagic shock and transported by air ambulance. We hypothesized that prehospital plasma would be...
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Clinical Research and Public Health In-Press Preview Immunology Inflammation

Prehospital plasma is associated with distinct biomarker expression following injury

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Abstract

Background: Prehospital plasma improves survival in severely injured trauma patients at risk for hemorrhagic shock and transported by air ambulance. We hypothesized that prehospital plasma would be associated with a reduction in immune imbalance and endothelial damage. Methods: We collected blood samples from 405 trauma patients enrolled in the Prehospital Air MedicalPlasma (PAMPer) trial upon hospital admission (0 hours) and 24 hours post admission across 6 U.S. sites(9 level-one trauma centers) with air medical transport services. We assayed samples for 21 inflammatory mediators and 7 markers of endothelial damage. We performed hierarchical clustering analysis (HCA) on principal components of these biomarkers of the immune response and endothelial injury. Regression analysis was used to control for known differences across study arms near the time of randomization and to assess any association with prehospital plasma administration. Results: HCA based on inflammatory mediator and endothelial damage marker concentrations distinguished two patient clusters, each with different injury patterns and outcomes. Patients in cluster A had greater injury severity and incidence of blunt trauma, traumatic brain injury, and mortality. Cluster A patients that received prehospital plasma as compared to standard care fluid resuscitation showed improved 30-day survival. Prehospital plasma did not improve survival in cluster B patients. In an adjusted analysis of themost seriously injured patients (ISS>30), plasma was associated with a an increase in circulating levels of adiponectin, IL-1β, IL-17A, IL-23, and IL-17E upon admission. One day following admission, prehospital plasmas was associated with a reduction in syndecan-1, TM, VEGF, IL-6, IP-10, MCP-1, and TNF-α, and an increase in IL-33, IL-21, IL-23, and IL-17E. Conclusion: This is the first human study to suggest that prehospital plasma may ameliorate the endotheliopathy of trauma and modulate an imbalance between pro-inflammatory (e.g. IL-6, TNF-α, and MCP-1) and protective (e.g. IL-33 and IL-17E) mediators. These effects of early plasma administration may contribute to improved survival in severely injured patients. Trial Registration: ClinicalTrials.gov NCT01818427 Funding: National Institutes of Health T32; U.S. Army Medical Research and Materiel Command W81XWH-12-2-0023; National Institutes of Health R35; National Institutes of Health 1R35GM119526-01; the Office of the Assistant Secretary of Defense for Health Affairs, through the Defense Medical Research and Development Program W81XWH-18-2-0051 and W81XWH-15-PRORP-OCRCA. Opinions, interpretations, conclusions and recommendations are those of the authors and not necessarily endorsed by the Department of Defense.

Authors

Danielle S. Gruen, Joshua B. Brown, Francis X. Guyette, Yoram Vodovotz, Par I. Johansson, Jakob Stensballe, Derek A. Barclay, Jinling Yin, Brian J. Daley, Richard S. Miller, Brian G. Harbrecht, Jeffrey A. Claridge, Herb A. Phelan, Matthew D. Neal, Brian Zuckerbraun, Timothy R. Billiar, Jason L. Sperry

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Glucose in the hypothalamic paraventricular nucleus regulates GLP-1 release
Glucokinase (GK) is highly expressed in the hypothalamic paraventricular nucleus (PVN); however its role is currently unknown. We found that glucokinase in the PVN acts as part of a glucose sensing...
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Research In-Press Preview Endocrinology Neuroscience

Glucose in the hypothalamic paraventricular nucleus regulates GLP-1 release

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Abstract

Glucokinase (GK) is highly expressed in the hypothalamic paraventricular nucleus (PVN); however its role is currently unknown. We found that glucokinase in the PVN acts as part of a glucose sensing mechanism within the PVN that regulates glucose homeostasis by controlling glucagon like peptide 1 (GLP-1) release. GLP-1 is released from enteroendocrine L-cells in response to oral glucose. Here we identify a brain mechanism critical to the release of GLP-1 in response to oral glucose. We show that increasing expression of GK or injection of glucose into the PVN increases GLP-1 release in response to oral glucose. On the contrary decreasing expression of GK or injection of non-metabolisable glucose into the PVN prevents GLP-1 release. Our results demonstrate that glucosensitive GK neurones in the PVN, are critical to the response to oral glucose and subsequent release of GLP-1.

Authors

Yue Ma, Risheka Ratnasabapathy, Ivan De Backer, Chioma Izzi-Engbeaya, Marie-Sophie Nguyen-Tu, Joyceline Cuenco, Ben Jones, Christopher D. John, Brian Y. H. Lam, Guy A. Rutter, Giles Yeo, Waljit Dhillo, James Gardiner

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