In this issue of JCI Insight, Raphael et al. provide evidence in mice that T cell-independent TNF receptor 2 (TNFR2) expression limits progression of neuroinflammatory disease by restraining pathogenic astrocyte functions and promoting remyelination. The cover image shows myelin (red), astrocytes (GFAP; green), and nuclei (DAPI, blue) in the cerebellum of transgenic mice in the progressive phase of experimental autoimmune encephalomyelitis (EAE).
Proteinuric chronic kidney disease (CKD) remains a major health problem worldwide. While it is well established that the progression of primary glomerular disease induces tubulointerstitial lesions, how tubular injury triggers glomerular damage is poorly understood. We hypothesized that injured tubules secrete mediators that adversely affect glomerular health. To test this, we used conditional knockout mice with tubule-specific ablation of β-catenin (Ksp-β-cat–/–) and subjected them to chronic angiotensin II (Ang II) infusion or Adriamycin. Compared with control mice, Ksp-β-cat–/– mice were dramatically protected from proteinuria and glomerular damage. MMP-7, a downstream target of β-catenin, was upregulated in treated control mice, but this induction was blunted in the Ksp-β-cat–/– littermates. Incubation of isolated glomeruli with MMP-7 ex vivo led to nephrin depletion and impaired glomerular permeability. Furthermore, MMP-7 specifically and directly degraded nephrin in cultured glomeruli or cell-free systems, and this effect was dependent on its proteolytic activity. In vivo, expression or infusion of exogenous MMP-7 caused proteinuria, and genetic ablation of MMP-7 protected mice from Ang II–induced proteinuria and glomerular injury. Collectively, these results demonstrate that β-catenin–driven MMP-7 release from renal tubules promotes glomerular injury via direct degradation of the key slit diaphragm protein nephrin.
Roderick J. Tan, Yingjian Li, Brittney M. Rush, Débora Malta Cerqueira, Dong Zhou, Haiyan Fu, Jacqueline Ho, Donna Beer Stolz, Youhua Liu
γδ T cells account for a large fraction of human intestinal intraepithelial lymphocytes (IELs) endowed with potent antitumor activities. However, little is known about their origin, phenotype, and clinical relevance in colorectal cancer (CRC). To determine γδ IEL gut specificity, homing, and functions, γδ T cells were purified from human healthy blood, lymph nodes, liver, skin, and intestine, either disease-free, affected by CRC, or generated from thymic precursors. The constitutive expression of NKp46 specifically identifies a subset of cytotoxic Vδ1 T cells representing the largest fraction of gut-resident IELs. The ontogeny and gut-tropism of NKp46+/Vδ1 IELs depends both on distinctive features of Vδ1 thymic precursors and gut-environmental factors. Either the constitutive presence of NKp46 on tissue-resident Vδ1 intestinal IELs or its induced expression on IL-2/IL-15–activated Vδ1 thymocytes are associated with antitumor functions. Higher frequencies of NKp46+/Vδ1 IELs in tumor-free specimens from CRC patients correlate with a lower risk of developing metastatic III/IV disease stages. Additionally, our in vitro settings reproducing CRC tumor microenvironment inhibited the expansion of NKp46+/Vδ1 cells from activated thymic precursors. These results parallel the very low frequencies of NKp46+/Vδ1 IELs able to infiltrate CRC, thus providing insights to either follow-up cancer progression or to develop adoptive cellular therapies.
Joanna Mikulak, Ferdinando Oriolo, Elena Bruni, Alessandra Roberto, Federico S. Colombo, Anna Villa, Marita Bosticardo, Ileana Bortolomai, Elena Lo Presti, Serena Meraviglia, Francesco Dieli, Stefania Vetrano, Silvio Danese, Silvia Della Bella, Michele M. Carvello, Matteo Sacchi, Giovanni Cugini, Giovanni Colombo, Marco Klinger, Paola Spaggiari, Massimo Roncalli, Immo Prinz, Sarina Ravens, Biagio di Lorenzo, Emanuela Marcenaro, Bruno Silva-Santos, Antonino Spinelli, Domenico Mavilio
BACKGROUND. The cytokine IL-7 is critical for T cell development and function. We performed a Phase Ib study in patients with type 1 diabetes (T1D) to evaluate how blockade of IL-7 would affect immune cells and relevant clinical responses. METHODS. Thirty-seven subjects with T1D received s.c. RN168, a monoclonal antibody that blocks the IL -7 receptor α (IL7Rα) in a dose-escalating study. RESULTS. Between 90% and 100% IL-7R occupancy and near-complete inhibition of pSTAT5 was observed at doses of RN168 1 mg/kg every other week (Q2wk) and greater. There was a significant decline in CD4+ and CD8+ effector and central memory T cells and CD4+ naive cells, but there were fewer effects on CD8+ naive T cells. The ratios of Tregs to CD4+ or CD8+ effector and central memory T cells versus baseline were increased. RNA sequencing analysis showed downmodulation of genes associated with activation, survival, and differentiation of T cells. Expression of the antiapoptotic protein Bcl-2 was reduced. The majority of treatment-emergent adverse events (TEAEs) were mild and not treatment related. Four subjects became anti–EBV IgG+ after RN168, and 2 had symptoms of active infection. The immunologic response to tetanus toxoid was preserved at doses of 1 and 3 mg/kg Q2wk but reduced at higher doses. CONCLUSIONS. This trial shows that, at dosages of 1–3 mg/kg, RN168 selectively inhibits the survival and activity of memory T cells while preserving naive T cells and Tregs. These immunologic effects may serve to eliminate pathologic T cells in autoimmune diseases. TRIAL REGISTRATION. NCT02038764. FUNDING. Pfizer Inc.
Kevan C. Herold, Samantha L. Bucktrout, Xiao Wang, Bruce W. Bode, Stephen E. Gitelman, Peter A. Gottlieb, Jing Hughes, Tenshang Joh, Janet B. McGill, Jeremy H. Pettus, Shobha Potluri, Desmond Schatz, Megan Shannon, Chandrasekhar Udata, Gilbert Wong, Matteo Levisetti, Bishu J. Ganguly, Pamela D. Garzone, the RN168 Working Group
Despite an unprecedented 2 decades of success, the combat against malaria — the mosquito-transmitted disease caused by Plasmodium parasites — is no longer progressing. Efforts toward eradication are threatened by the lack of an effective vaccine and a rise in antiparasite drug resistance. Alternative approaches are urgently needed. Repurposing of available, approved drugs with distinct modes of action are being considered as viable and immediate adjuncts to standard antimicrobial treatment. Such strategies may be well suited to the obligatory and clinically silent first phase of Plasmodium infection, where massive parasite replication occurs within hepatocytes in the liver. Here, we report that the widely used antidiabetic drug, metformin, impairs parasite liver stage development of both rodent-infecting Plasmodium berghei and human-infecting P. falciparum parasites. Prophylactic treatment with metformin curtails parasite intracellular growth in vitro. An additional effect was observed in mice with a decrease in the numbers of infected hepatocytes. Moreover, metformin provided in combination with conventional liver- or blood-acting antimalarial drugs further reduced the total burden of P. berghei infection and substantially lessened disease severity in mice. Together, our findings indicate that repurposing of metformin in a prophylactic regimen could be considered for malaria chemoprevention.
Iset Medina Vera, Margarida T. Grilo Ruivo, Leonardo F. Lemos Rocha, Sofia Marques, Sangeeta N. Bhatia, Maria M. Mota, Liliana Mancio-Silva
Clinical and preclinical studies show tissue-specific differences in tumorigenesis. Tissue specificity is controlled by differential gene expression. We prioritized genes that encode secreted proteins according to their preferential expression in normal lungs to identify candidates associated with lung cancer. Indeed, most of the lung-enriched genes identified in our analysis have known or suspected roles in lung cancer. We focused on the gene encoding neuron-derived neurotrophic factor (NDNF), which had not yet been associated with lung cancer. We determined that NDNF was preferentially expressed in the normal adult lung and that its expression was decreased in human lung adenocarcinoma and a mouse model of this cancer. Higher expression of NDNF was associated with better clinical outcome of patients with lung adenocarcinoma. Purified NDNF inhibited proliferation of lung cancer cells, whereas silencing NDNF promoted tumor cell growth in culture and in xenograft models. We determined that NDNF is downregulated through DNA hypermethylation near CpG island shores in human lung adenocarcinoma. Furthermore, the lung cancer–related DNA hypermethylation sites corresponded to the methylation sites that occurred in tissues with low NDNF expression. Thus, by analyzing the tissue-specific secretome, we identified a tumor-suppressive factor, NDNF, which is associated with patient outcomes in lung adenocarcinoma.
Ya Zhang, Xuefeng Wu, Yan Kai, Chia-Han Lee, Fengdong Cheng, Yixuan Li, Yongbao Zhuang, Javid Ghaemmaghami, Kun-Han Chuang, Zhuo Liu, Yunxiao Meng, Meghana Keswani, Nancy R. Gough, Xiaojun Wu, Wenge Zhu, Alexandros Tzatsos, Weiqun Peng, Edward Seto, Eduardo M. Sotomayor, Xiaoyan Zheng
Distinct subsets of Tregs reside in nonlymphoid tissues where they mediate unique functions. To interrogate the biology of tissue Tregs in human health and disease, we phenotypically and functionally compared healthy skin Tregs with those in peripheral blood, inflamed psoriatic skin, and metastatic melanoma. The mitochondrial enzyme, arginase 2 (ARG2), was preferentially expressed in Tregs in healthy skin, increased in Tregs in metastatic melanoma, and reduced in Tregs from psoriatic skin. ARG2 enhanced Treg suppressive capacity in vitro and conferred a selective advantage for accumulation in inflamed tissues in vivo. CRISPR-mediated deletion of this gene in primary human Tregs was sufficient to skew away from a tissue Treg transcriptional signature. Notably, the inhibition of ARG2 increased mTOR signaling, whereas the overexpression of this enzyme suppressed it. Taken together, our results suggest that Tregs express ARG2 in human tissues to both regulate inflammation and enhance their metabolic fitness.
Margaret M. Lowe, Ian Boothby, Sean Clancy, Richard S. Ahn, Wilson Liao, David N. Nguyen, Kathrin Schumann, Alexander Marson, Kelly M. Mahuron, Gillian A. Kingsbury, Zheng Liu, Priscila Munoz Sandoval, Robert Sanchez Rodriguez, Mariela L. Pauli, Keyon Taravati, Sarah T. Arron, Isaac M. Neuhaus, Hobart W. Harris, Esther A. Kim, Uk Sok Shin, Matthew F. Krummel, Adil Daud, Tiffany C. Scharschmidt, Michael D. Rosenblum
Accumulation of senescent cells is associated with the progression of pulmonary fibrosis, but mechanisms accounting for this linkage are not well understood. To explore this issue, we investigated whether a class of biologically active profibrotic lipids, the leukotrienes (LT), is part of the senescence-associated secretory phenotype. The analysis of conditioned medium (CM), lipid extracts, and gene expression of LT biosynthesis enzymes revealed that senescent cells secreted LT, regardless of the origin of the cells or the modality of senescence induction. The synthesis of LT was biphasic and followed by antifibrotic prostaglandin (PG) secretion. The LT-rich CM of senescent lung fibroblasts (IMR-90) induced profibrotic signaling in naive fibroblasts, which were abrogated by inhibitors of ALOX5, the principal enzyme in LT biosynthesis. The bleomycin-induced expression of genes encoding LT and PG synthases, level of cysteinyl LT in the bronchoalveolar lavage, and overall fibrosis were reduced upon senescent cell removal either in a genetic mouse model or after senolytic treatment. Quantification of ALOX5+ cells in lung explants obtained from idiopathic pulmonary fibrosis (IPF) patients indicated that half of these cells were also senescent (p16Ink4a+). Unlike human fibroblasts from unused donor lungs made senescent by irradiation, senescent IPF fibroblasts secreted LTs but failed to synthesize PGs. This study demonstrates for the first time to our knowledge that senescent cells secrete functional LTs, significantly contributing to the LT pool known to cause or exacerbate IPF.
Christopher D. Wiley, Alexis N. Brumwell, Sonnet S. Davis, Julia R. Jackson, Alexis Valdovinos, Cheresa Calhoun, Fatouma Alimirah, Carlos A. Castellanos, Richard Ruan, Ying Wei, Harold A. Chapman, Arvind Ramanathan, Judith Campisi, Claude Jourdan Le Saux
Patients with Duchenne muscular dystrophy (DMD) commonly present with severe ventricular arrhythmias that contribute to heart failure. Arrhythmias and lethality are also consistently observed in adult Dmdmdx mice, a mouse model of DMD, after acute β-adrenergic stimulation. These pathological features were previously linked to aberrant expression and remodeling of the cardiac gap junction protein connexin43 (Cx43). Here, we report that remodeled Cx43 protein forms Cx43 hemichannels in the lateral membrane of Dmdmdx cardiomyocytes and that the β-adrenergic agonist isoproterenol (Iso) aberrantly activates these hemichannels. Block of Cx43 hemichannels or a reduction in Cx43 levels (using Dmdmdx Cx43+/– mice) prevents the abnormal increase in membrane permeability, plasma membrane depolarization, and Iso-evoked electrical activity in these cells. Additionally, Iso treatment promotes nitric oxide (NO) production and S-nitrosylation of Cx43 hemichannels in Dmdmdx heart. Importantly, inhibition of NO production prevents arrhythmias evoked by Iso. We found that NO directly activates Cx43 hemichannels by S-nitrosylation of cysteine at position 271. Our results demonstrate that opening of remodeled and S-nitrosylated Cx43 hemichannels plays a key role in the development of arrhythmias in DMD mice and that these channels may serve as therapeutic targets to prevent fatal arrhythmias in patients with DMD .
Mauricio A. Lillo, Eric Himelman, Natalia Shirokova, Lai-Hua Xie, Diego Fraidenraich, Jorge E. Contreras
BACKGROUND Bacille Calmette-Guérin (BCG) vaccine is protective against Tuberculosis (TB) in children, but its efficacy wanes with age. Consequently, determining if BCG revaccination augments anti-TB immunity in young adults in TB endemic regions is vital.METHODS Two hundred healthy adults, BCG vaccinated at birth, were tested for their IFN-γ release assay (IGRA) status. Of these, 28 IGRA+ and 30 IGRA– were BCG revaccinated, and 24 IGRA+ and 23 IGRA– subjects served as unvaccinated controls. T and innate cell responses to mycobacterial antigens were analyzed by 14-color flow cytometry over 34 weeks.RESULTS IFN-γ and/or IL-2 Ag85A- and BCG-specific CD4+ and CD8+ T cell responses were boosted by revacciantion at 4 and 34 weeks, respectively, and were > 2-fold higher in IGRA+ compared with IGRA– vaccinees. Polyfunctional Ag85A, BCG, and mycobacterium tuberculosis (Mtb) latency Ag–specific (LTAg-specific) CD4+ T cells expressing up to 8 cytokines were also significantly enhanced in both IGRA+ and IGRA– vaccinees relative to unvaccinated controls, most markedly in IGRA+ vaccinees. A focused analysis of Th17 responses revealed expansion of Ag85A-, BCG-, and LTAg-specific total IL-17A+,IL-17F+,IL-22+, and IL-10+ CD4+ T cell effectors in both IGRA+ and IGRA– subjects. Also, innate IFN-γ+ NK/γδ/NKT cell responses were higher in both IGRA+ and IGRA– vaccinees compared with controls. This is the first evidence to our knowledge that BCG revaccination significantly boosts antimycobacterial Th1/Th17 responses in IGRA+ and IGRA– subjects.CONCLUSION These data show that BCG revaccination is immunogenic in IGRA– and IGRA+ subjects, implying that Mtb preinfection in IGRA+ subjects does not impact immunogenicity. This has implications for public health and vaccine development strategies.FUNDING This work was funded principally by DBT-NIH (BT/MB/Indo-US/HIPC/2013).
Srabanti Rakshit, Asma Ahmed, Vasista Adiga, Bharath K. Sundararaj, Pravat Nalini Sahoo, John Kenneth, George D’Souza, Wesley Bonam, Christina Johnson, Kees L.M.C. Franken, Tom H.M. Ottenhoff, Greg Finak, Raphael Gottardo, Kenneth D. Stuart, Stephen C. De Rosa, M. Juliana McElrath, Annapurna Vyakarnam
Immune checkpoint inhibitor (ICI) treatment has recently become a first-line therapy for many non–small cell lung cancer (NSCLC) patients. Unfortunately, most NSCLC patients are refractory to ICI monotherapy, and initial attempts to address this issue with secondary therapeutics have proven unsuccessful. To identify entities precluding CD8+ T cell accumulation in this process, we performed unbiased analyses on flow cytometry, gene expression, and multiplexed immunohistochemical data from a NSCLC patient cohort. The results revealed the presence of a myeloid-rich subgroup, which was devoid of CD4+ and CD8+ T cells. Of all myeloid cell types assessed, neutrophils were the most highly associated with the myeloid phenotype. Additionally, the ratio of CD8+ T cells to neutrophils (CD8/PMN) within the tumor mass optimally distinguished between active and myeloid cases. This ratio was also capable of showing the separation of patients responsive to ICI therapy from those with stable or progressive disease in 2 independent cohorts. Tumor-bearing mice treated with a combination of anti-PD1 and SX-682 (CXCR1/2 inhibitor) displayed relocation of lymphocytes from the tumor periphery into a malignant tumor, which was associated with induction of IFN-γ–responsive genes. These results suggest that neutrophil antagonism may represent a viable secondary therapeutic strategy to enhance ICI treatment outcomes.
Julia Kargl, Xiaodong Zhu, Huajia Zhang, Grace H. Y. Yang, Travis J. Friesen, Melissa Shipley, Dean Y. Maeda, John A. Zebala, Jill McKay-Fleisch, Gavin Meredith, Afshin Mashadi-Hossein, Christina Baik, Robert H. Pierce, Mary W. Redman, Jeffrey C. Thompson, Steven M. Albelda, Hamid Bolouri, A. McGarry Houghton
Conventional treatments for inflammatory bowel disease (IBD) have multiple potential side effects. Therefore, alternative treatments are desperately needed. This work demonstrated that systemic administration of exosomes from human bone marrow–derived mesenchymal stromal cells (MSC-Exos) substantially mitigated colitis in various models of IBD. MSC-Exos treatment downregulated inflammatory responses, maintained intestinal barrier integrity, and polarized M2b macrophages but did not favor intestinal fibrosis. Mechanistically, infused MSC-Exos acted mainly on colonic macrophages, and macrophages from colitic colons acquired obvious resistance to inflammatory restimulation when prepared from mice treated with MSC-Exos versus untreated mice. The beneficial effect of MSC-Exos was blocked by macrophage depletion. Also, the induction of IL-10 production from macrophages was partially involved in the beneficial effect of MSC-Exos. MSC-Exos were enriched in proteins involved in regulating multiple biological processes associated with the anticolitic benefit of MSC-Exos. Particularly, metallothionein-2 in MSC-Exos was required for the suppression of inflammatory responses. Taken together, MSC-Exos are critical regulators of inflammatory responses and may be promising candidates for IBD treatment.
Huashan Liu, Zhenxing Liang, Fengwei Wang, Chi Zhou, Xiaobin Zheng, Tuo Hu, Xiaowen He, Xianrui Wu, Ping Lan
BACKGROUND The airways of obese asthmatics have been shown to be NO deficient, and this contributes to airway dysfunction and reduced response to inhaled corticosteroids. In cultured airway epithelial cells, L-citrulline, a precursor of L-arginine recycling and NO formation, has been shown to prevent asymmetric dimethyl arginine–mediated (ADMA-mediated) NO synthase (NOS2) uncoupling, restoring NO and reducing oxidative stress.METHODS In a proof-of-concept, open-label pilot study in which participants were analyzed before and after treatment, we hypothesized that 15 g/d L-citrulline for 2 weeks would (a) increase the fractional excretion of NO (FeNO), (b) improve asthma control, and (c) improve lung function. To this end, we recruited obese (BMI >30) asthmatics on controller therapy, with a baseline FeNO of ≤30 ppb from the University of Colorado Medical Center and Duke University Health System.RESULTS A total of 41 subjects with an average FeNO of 17 ppb (95% CI, 15–19) and poorly controlled asthma (average asthma control questionnaire [ACQ] 1.5 [95% CI, 1.2–1.8]) completed the study. Compared with baseline, L-citrulline increased whereas ADMA and arginase concentration did not (values represent the mean Δ and 95% CI): plasma L-citrulline (190 μM, 84–297), plasma L-arginine (67 μM, 38–95), and plasma L-arginine/ADMA (ratio 117, 67–167). FeNO increased by 4.2 ppb (1.7–6.7 ppb); ACQ decreased by –0.46 (–0.67 to 0.27 points); the forced vital capacity and forced exhalation volume in 1 second, respectively, changed by 86 ml (10–161 ml) and 52 ml (–11 to 132 ml). In a secondary analysis, the greatest FEV1 increments occurred in those subjects with late-onset asthma (>12 years) (63 ml [95% CI, 1–137]), in females (80 ml [95% CI, 5–154]), with a greater change seen in late-onset females (100 ml, [95% CI, 2–177]). The changes in lung function or asthma control were not significantly associated with the changes before and after treatment in L-arginine/ADMA or FeNO.CONCLUSION Short-term L-citrulline treatment improved asthma control and FeNO levels in obese asthmatics with low or normal FeNO. Larger FEV1 increments were observed in those with late-onset asthma and in females.TRIAL REGISTRATION ClinicalTrials.gov NCT01715844.FUNDING NIH NHLBI R01 HL146542-01.
Fernando Holguin, Hartmut Grasemann, Sunita Sharma, Daniel Winnica, Karen Wasil, Vong Smith, Margaret H. Cruse, Nancy Perez, Erika Coleman, Timothy J. Scialla, Loretta G. Que
The HER2-specific monoclonal antibody (mAb), trastuzumab, has been the mainstay of therapy for HER2+ breast cancer (BC) for approximately 20 years. However, its therapeutic mechanism of action (MOA) remains unclear, with antitumor responses to trastuzumab remaining heterogeneous and metastatic HER2+ BC remaining incurable. Consequently, understanding its MOA could enable rational strategies to enhance its efficacy. Using both murine and human versions of trastuzumab, we found its antitumor activity dependent on Fcγ receptor stimulation of tumor-associated macrophages (TAMs) and antibody-dependent cellular phagocytosis (ADCP), but not cellular cytotoxicity (ADCC). Trastuzumab also stimulated TAM activation and expansion, but did not require adaptive immunity, natural killer cells, and/or neutrophils. Moreover, inhibition of the innate immune ADCP checkpoint, CD47, significantly enhanced trastuzumab-mediated ADCP and TAM expansion and activation, resulting in the emergence of a unique hyperphagocytic macrophage population, improved antitumor responses, and prolonged survival. In addition, we found that tumor-associated CD47 expression was inversely associated with survival in HER2+ BC patients and that human HER2+ BC xenografts treated with trastuzumab plus CD47 inhibition underwent complete tumor regression. Collectively, our study identifies trastuzumab-mediated ADCP as an important antitumor MOA that may be clinically enabled by CD47 blockade to augment therapeutic efficacy.
Li-Chung Tsao, Erika J. Crosby, Timothy N. Trotter, Pankaj Agarwal, Bin-Jin Hwang, Chaitanya Acharya, Casey W. Shuptrine, Tao Wang, Junping Wei, Xiao Yang, Gangjun Lei, Cong-Xiao Liu, Christopher A. Rabiola, Lewis A. Chodosh, William J. Muller, Herbert Kim Lyerly, Zachary C. Hartman
Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome immunodeficiency is caused by autosomal dominant gain-of-function mutations in chemokine receptor CXCR4. Patient WHIM-09 was spontaneously cured by chromothriptic deletion of 1 copy of 164 genes, including the CXCR4WHIM allele, presumably in a single hematopoietic stem cell (HSC) that repopulated HSCs and the myeloid lineage. Testing the specific contribution of CXCR4 hemizygosity to her cure, we previously demonstrated enhanced engraftment of Cxcr4+/o HSCs after transplantation in WHIM (Cxcr4+/w) model mice, but the potency was not quantitated. We now report graded-dose competitive transplantation experiments using lethally irradiated Cxcr4+/+ recipients in which mixed BM cells containing approximately 5 Cxcr4+/o HSCs and a 100-fold excess of Cxcr4+/w HSCs achieved durable 50% Cxcr4+/o myeloid and B cell chimerism in blood and approximately 20% Cxcr4+/o HSC chimerism in BM. In Cxcr4+/o/Cxcr4+/w parabiotic mice, we observed 80%–100% Cxcr4+/o myeloid and lymphoid chimerism in the blood and 15% Cxcr4+/o HSC chimerism in BM from the Cxcr4+/w parabiont, which was durable after separation from the Cxcr4+/o parabiont. Thus, CXCR4 haploinsufficiency likely significantly contributed to the selective repopulation of HSCs and the myeloid lineage from a single chromothriptic HSC in WHIM-09. Moreover, the results suggest that WHIM allele silencing of patient HSCs is a viable gene therapy strategy.
Ji-Liang Gao, Albert Owusu-Ansah, Andrea Paun, Kimberly Beacht, Erin Yim, Marie Siwicki, Alexander Yang, Qian Liu, David H. McDermott, Philip M. Murphy
In humans, chronic glucocorticoid use is associated with side effects like muscle wasting, obesity, and metabolic syndrome. Intermittent steroid dosing has been proposed in Duchenne Muscular Dystrophy patients to mitigate the side effects seen with daily steroid intake. We evaluated biomarkers from Duchenne Muscular Dystrophy patients, finding that, compared with chronic daily steroid use, weekend steroid use was associated with reduced serum insulin, free fatty acids, and branched chain amino acids, as well as reduction in fat mass despite having similar BMIs. We reasoned that intermittent prednisone administration in dystrophic mice would alter muscle epigenomic signatures, and we identified the coordinated action of the glucocorticoid receptor, KLF15 and MEF2C as mediators of a gene expression program driving metabolic reprogramming and enhanced nutrient utilization. Muscle lacking Klf15 failed to respond to intermittent steroids. Furthermore, coadministration of the histone acetyltransferase inhibitor anacardic acid with steroids in mdx mice eliminated steroid-specific epigenetic marks and abrogated the steroid response. Together, these findings indicate that intermittent, repeated exposure to glucocorticoids promotes performance in dystrophic muscle through an epigenetic program that enhances nutrient utilization.
Mattia Quattrocelli, Aaron S. Zelikovich, Zhen Jiang, Clara Bien Peek, Alexis R. Demonbreun, Nancy L. Kuntz, Grant D. Barish, Saptarsi M. Haldar, Joseph Bass, Elizabeth M. McNally
Multiple sclerosis (MS) is an autoimmune neuroinflammatory disease where the underlying mechanisms driving disease progression have remained unresolved. HLA-DR2b (DRB1*15:01) is the most common genetic risk factor for MS. Additionally, TNF and its receptors TNFR1 and TNFR2 play key roles in MS and its preclinical animal model, experimental autoimmune encephalomyelitis (EAE). TNFR2 is believed to ameliorate CNS pathology by promoting remyelination and Treg function. Here, we show that transgenic mice expressing the human MHC class II (MHC-II) allele HLA-DR2b and lacking mouse MHC-II and TNFR2 molecules, herein called DR2bΔR2, developed progressive EAE, while disease was not progressive in DR2b littermates. Mechanistically, expression of the HLA-DR2b favored Th17 cell development, whereas T cell–independent TNFR2 expression was critical for restraining of an astrogliosis-induced proinflammatory milieu and Th17 cell responses, while promoting remyelination. Our data suggest the TNFR2 signaling pathway as a potentially novel mechanism for curtailing astrogliosis and promoting remyelination, thus providing new insights into mechanisms limiting progressive MS.
Itay Raphael, Francisco Gomez-Rivera, Rebecca A. Raphael, Rachel R. Robinson, Saisha Nalawade, Thomas G. Forsthuber
BACKGROUND Hepatic encephalopathy (HE) is associated with poor outcomes. A prior randomized, pilot trial demonstrated safety after oral capsular fecal microbial transplant (FMT) in HE, with favorable changes in microbial composition and cognition. However, microbial functional changes are unclear. The aim of this study was to determine the effect of FMT on the gut-brain axis compared with placebo, using microbial function based on bile acids (BAs), inflammation (serum IL-6, LPS-binding protein [LBP]), and their association with EncephalApp.METHODS Twenty cirrhotic patients were randomized 1:1 into groups that received 1-time FMT capsules from a donor enriched in Lachnospiraceae and Ruminococcaceae or placebo capsules, with 5-month follow-up for safety outcomes. Stool microbiota and BA; serum IL-6, BA, and LBP; and EncephalApp were analyzed at baseline and 4 weeks after FMT/placebo. Correlation networks among microbiota, BAs, EncephalApp, IL-6, and LBP were performed before/after FMT.RESULTS FMT-assigned participants had 1 HE recurrence and 2 unrelated infections. Six placebo-assigned participants developed negative outcomes. FMT, but not placebo, was associated with reduced serum IL-6 and LBP and improved EncephalApp. FMT-assigned participants demonstrated higher deconjugation and secondary BA formation in feces and serum compared with baseline. No change was seen in placebo. Correlation networks showed greater complexity after FMT compared with baseline. Beneficial taxa, such as Ruminococcaceae, Verrucomicrobiaceae, and Lachnospiraceae, were correlated with cognitive improvement and decrease in inflammation after FMT. Fecal/serum secondary/primary ratios and PiCRUST secondary BA pathways did not increase in participants who developed poor outcomes.CONCLUSION Gut microbial function in cirrhosis is beneficially affected by capsular FMT, with improved inflammation and cognition. Lower secondary BAs in FMT recipients could select for participants who develop negative outcomes.TRIAL REGISTRATION Clinicaltrials.gov NCT03152188.FUNDING National Center for Advancing Translational Sciences NIH grant R21TR002024, VA Merit Review grant 2I0CX001076, the United Kingdom National Institute for Health Research Biomedical Facility at Imperial College London, the British Heart Foundation, Wellcome Trust, and King’s College London.
Jasmohan S. Bajaj, Nita Salzman, Chathur Acharya, Hajime Takei, Genta Kakiyama, Andrew Fagan, Melanie B. White, Edith A. Gavis, Mary L. Holtz, Michael Hayward, Hiroshi Nittono, Phillip B. Hylemon, I. Jane Cox, Roger Williams, Simon D. Taylor-Robinson, Richard K. Sterling, Scott C. Matherly, Michael Fuchs, Hannah Lee, Puneet Puri, R. Todd Stravitz, Arun J. Sanyal, Lola Ajayi, Adrien Le Guennec, R. Andrew Atkinson, Mohammad S. Siddiqui, Velimir Luketic, William M. Pandak, Masoumeh Sikaroodi, Patrick M. Gillevet
As sufficient extracellular arginine is crucial for T cell function, depletion of extracellular arginine by elevated arginase 1 (Arg1) activity has emerged as a hallmark immunosuppressive mechanism. However, the potential cell-autonomous roles of arginases in T cells have remained unexplored. Here, we show that the arginase isoform expressed by T cells, the mitochondrial Arg2, is a cell-intrinsic regulator of CD8+ T cell activity. Both germline Arg2 deletion and adoptive transfer of Arg2–/– CD8+ T cells significantly reduced tumor growth in preclinical cancer models by enhancing CD8+ T cell activation, effector function, and persistence. Transcriptomic, proteomic, and high-dimensional flow cytometry characterization revealed a CD8+ T cell–intrinsic role of Arg2 in modulating T cell activation, antitumor cytoxicity, and memory formation, independently of extracellular arginine availability. Furthermore, specific deletion of Arg2 in CD8+ T cells strongly synergized with PD-1 blockade for the control of tumor growth and animal survival. These observations, coupled with the finding that pharmacologic arginase inhibition accelerates activation of ex vivo human T cells, unveil Arg2 as a potentially new therapeutic target for T cell–based cancer immunotherapies.
Adrià-Arnau Martí i Líndez, Isabelle Dunand-Sauthier, Mark Conti, Florian Gobet, Nicolás Núñez, J. Thomas Hannich, Howard Riezman, Roger Geiger, Alessandra Piersigilli, Kerstin Hahn, Sylvain Lemeille, Burkhard Becher, Thibaut De Smedt, Stéphanie Hugues, Walter Reith
Massive tears of the rotator cuff (RC) are associated with chronic muscle degeneration due to fibrosis, fatty infiltration, and muscle atrophy. The microenvironment of diseased muscle often impairs efficient engraftment and regenerative activity of transplanted myogenic precursors. Accumulating myofibroblasts and fat cells disrupt the muscle stem cell niche and myogenic cell signaling and deposit excess disorganized connective tissue. Therefore, restoration of the damaged stromal niche with non–fibro-adipogenic cells is a prerequisite to successful repair of an injured RC. We generated from human embryonic stem cells (hES) a potentially novel subset of PDGFR-β+CD146+CD34–CD56– pericytes that lack expression of the fibro-adipogenic cell marker PDGFR-α. Accordingly, the PDGFR-β+PDGFR-α– phenotype typified non–fibro-adipogenic, non-myogenic, pericyte-like derivatives that maintained non–fibro-adipogenic properties when transplanted into chronically injured murine RCs. Although administered hES pericytes inhibited developing fibrosis at early and late stages of progressive muscle degeneration, transplanted PDGFR-β+PDGFR-α+ human muscle-derived fibro-adipogenic progenitors contributed to adipogenesis and greater fibrosis. Additionally, transplanted hES pericytes substantially attenuated muscle atrophy at all tested injection time points after injury. Coinciding with this observation, conditioned medium from cultured hES pericytes rescued atrophic myotubes in vitro. These findings imply that non–fibro-adipogenic hES pericytes recapitulate the myogenic stromal niche and may be used to improve cell-based treatments for chronic muscle disorders.
Gina M. Mosich, Regina Husman, Paras Shah, Abhinav Sharma, Kevin Rezzadeh, Temidayo Aderibigbe, Vivian J. Hu, Daniel J. McClintick, Genbin Wu, Jonathan D. Gatto, Haibin Xi, April D. Pyle, Bruno Péault, Frank A. Petrigliano, Ayelet Dar