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Abstract
Background: Dietary sodium intake mismatches urinary sodium excretion over prolonged periods. Our aims were to localize and quantify electrostatically bound sodium within human skin using triple quantum filtered (TQF) protocols for magnetic resonance imaging (MRI) and spectroscopy (MRS), and explore dermal sodium in Type 2 Diabetes Mellitus (T2D). Methods: We recruited adult participants with T2D (n=9) and euglycemic participants with no history of Diabetes Mellitus (n=8). All had undergone lower limb amputations or abdominal skin reduction surgery for clinical purposes. We used 20μm in-plane resolution 1H MRI to visualise anatomical skin regions ex vivo from skin biopsies taken intra-operatively, 23Na TQF MRI/MRS to explore distribution and quantification of freely dissolved and bound sodium and Inductively Coupled Plasma Mass Spectrometry to quantify sodium in selected skin samples. Results: Human dermis has a preponderance (>90%) of bound sodium that co-localizes with the glycosaminoglycan (GAG) scaffold. Bound and free sodium have similar anatomical locations. T2D associates with a severely reduced dermal bound sodium capacity. Conclusion: We provide the first evidence for high levels of bound sodium within human dermis, co-locating to the GAG scaffold, consistent with a dermal ‘third space repository’ for sodium. T2D associates with diminished dermal electrostatic binding capacity for sodium.
Authors
Petra Hanson, Christopher J. Philp, Harpal S. Randeva, Sean James, J Paul O'Hare, Thomas Meersmann, Galina E. Pavlovskaya, Thomas M. Barber
Abstract
Metastases cause 90% of human cancer deaths. The metastatic cascade involves local invasion, intravasation, extravasation, metastatic site colonization, and proliferation. While individual mediators of these processes have been investigated, interactions between these mediators remain less well defined. We previously identified a complex between receptor tyrosine kinase c-Met and β1 integrin in metastases. Using novel cell culture and in vivo assays, we found that c-Met/β1 complex induction promotes intravasation and vessel wall adhesion in triple-negative breast cancer cells, but does not increase extravasation. These effects may be driven by the ability of the c-Met/β1 complex to increase mesenchymal and stem cell characteristics. Multiplex transcriptomic analysis revealed upregulated Wnt and hedgehog pathways after c-Met/β1 complex induction. A β1 integrin point mutation that prevented binding to c-Met reduced intravasation. OS2966, a therapeutic antibody disrupting c-Met/β1 binding, decreased breast cancer cell invasion and mesenchymal gene expression. Bone-seeking breast cancer cells exhibited higher c-Met/β1 complex levels than parental controls and preferentially adhered to tissue-specific matrix. Patient bone metastases demonstrated higher c-Met/β1 complex than brain metastases. Thus, the c-Met/β1 complex drives intravasation of triple-negative breast cancer cells and preferential affinity for bone-specific matrix. Pharmacological targeting of the complex may prevent metastases, particularly osseous metastases.
Authors
Darryl Lau, Harsh Wadhwa, Sweta Sudhir, Alexander Chih-Chieh Chang, Saket Jain, Ankush Chandra, Alan T. Nguyen, Jordan M. Spatz, Ananya Pappu, Sumedh S. Shah, Justin Cheng, Michael M. Safaee, Garima Yagnik, Arman Jahangiri, Manish K. Aghi
Abstract
Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare but serious disease with poorly understood mechanisms. Here we report that patients with EGPA have elevated levels of TSLP, IL-25, and sST2, well characterized cytokine “alarmins” that activate or modulate type 2 innate lymphoid cells (ILC2s). Patients with active EGPA have a concurrent reduction in circulating ILC2s, suggesting a role for ILC2s in the pathogenesis of this disease. To explore the mechanism of these findings in patients, we established a model of EGPA in which active vasculitis and pulmonary hemorrhage are induced by IL-33 administration in predisposed, hypereosinophilic mice. In this model, induction of pulmonary hemorrhage and vasculitis is dependent on ILC2s and signaling through IL4Ra. In the absence of IL4Ra or STAT6, IL-33-treated mice have less vascular leak and pulmonary edema, less endothelial activation, and reduced eotaxin production, cumulatively leading to a reduction of pathologic eosinophil migration into the lung parenchyma. These results offer a mouse model for use in future mechanistic studies of EGPA, and suggest that IL-33, ILC2s and IL4Ra signaling may be potential targets for further study and therapeutic targeting in patients with EGPA.
Authors
Maya E. Kotas, Jérémie Dion, Steven Van Dyken, Roberto R. Ricardo-Gonzalez, Claire J. Danel, Camille Taillé, Luc Mouthon, Richard M. Locksley, Benjamin Terrier
Natural killer cells associate with amyotrophic lateral sclersois in a sex- and age-dependent manner
Abstract
NK cells are innate immune cells implicated in ALS; whether NK cells impact ALS in a sex- and age-specific manner was investigated. In mice, NK cells were depleted in male and female SOD1G93A ALS mice, survival and neuroinflammation were assessed, and data were stratified by sex. NK cell depletion extended survival in female but not male ALS mice with sex-specific effects on spinal cord microglia. In humans, NK cell numbers, NK cell subpopulations, and NK cell surface markers were examined in prospectively collected blood from ALS and control subjects; longitudinal changes in these metrics were correlated to Revised ALS Functional Rating Scale (ALSFRS-R) slope and stratified by sex and age. Expression of NK cell trafficking and cytotoxicity markers were elevated in ALS subjects, and changes in CXCR3+ NK cells and seven trafficking and cytotoxicity markers (CD11a, CD11b, CD38, CX3CR1, NKG2D, NKp30, NKp46) correlated with disease progression. Age impacted the associations between ALSFRS-R and markers NKG2D and NKp46, while sex impacted the NKp30 association. Collectively, these findings suggest that NK cells contribute to ALS progression in a sex- and age-specific manner and demonstrate that age and sex are critical variables when designing and assessing ALS immunotherapy.
Authors
Benjamin J. Murdock, Joshua P. Famie, Caroline E. Piecuch, Kristen D. Raue, Faye E. Mendelson, Cole H. Pieroni, Sebastian D. Iniguez, Lili Zhao, Stephen A. Goutman, Eva L. Feldman
Abstract
BACKGROUND. Whether airspace biomarkers add value to plasma biomarkers in studying ARDS is not well understood. Mesenchymal stromal cells (MSCs) are an investigational therapy for ARDS, and airspace biomarkers may provide mechanistic evidence for MSCs' impact in patients with ARDS. METHODS. We carried out a nested cohort study within a phase 2a safety trial of treatment with allogeneic MSCs for moderate to severe ARDS. Non-bronchoscopic bronchoalveolar lavage and plasma samples were collected 48 hours after study drug infusion. Airspace and plasma biomarker concentrations were compared between the MSC (n = 17) and placebo (n = 10) treatment arms, and correlation between the two compartments was tested. Airspace biomarkers were also tested for associations with clinical and radiographic outcomes. RESULTS. Compared to placebo, MSC treatment significantly reduced airspace total protein, angiopoietin-2 (Ang-2), interleukin-6 (IL-6), and soluble tumor necrosis factor receptor-1 concentrations. Plasma biomarkers did not differ between groups. Each 10-fold increase in airspace Ang-2 was independently associated with 6.7 fewer days alive and free of mechanical ventilation (95% CI -12.3 to -1.0, p = 0.023), and each 10-fold increase in airspace receptor for advanced glycation end-products (RAGE) was independently associated with a 6.6 point increase in day 3 radiographic assessment of lung edema score (95% CI 2.4 to 10.7, p = 0.004). CONCLUSIONS. MSCs reduced biological evidence of lung injury in patients with ARDS. Biomarkers from the airspaces provide additional value for studying pathogenesis, treatment effects, and outcomes in ARDS. TRIAL REGISTRATION. NCT02097641 FUNDING. National Heart, Lung, and Blood Institute
Authors
Katherine D. Wick, Aleksandra Leligdowicz, Hanjing Zhuo, Lorraine B. Ware, Michael A. Matthay
Abstract
BACKGROUND. Assessment of risk for chronic kidney disease (CKD) after acute kidney injury (AKI) is based on a limited set of markers primarily reflecting glomerular function. We evaluated markers of cell integrity (EGF) and inflammation (monocyte chemoattractant protein-1 [MCP-1]) for predicting long-term kidney outcomes after cardiac surgery. METHODS. We measured the urinary biomarkers EGF and MCP-1 in pre- and post-operative urine samples from 865 adult patients who underwent cardiac surgery from 2007–2010 at 2 sites in Canada and the United States and assessed their associations with the composite outcome of CKD incidence or progression. We also used single-cell (Sc) RNAseq of biopsies from patients with AKI to perform a transcriptomic analysis of programs that are coregulated with the genes encoding the 2 biomarkers. RESULTS. Over a median (IQR) follow-up of 5.8 (4.2-7.1) years, 266 (30.8%) patients developed the composite CKD outcome. Post-operatively, higher levels of urinary EGF were protective and higher levels of MCP-1 were associated with the composite CKD outcome (adjusted HR 0.83, 95% CI 0.73-0.95 and 1.10, 95% CI 1.00-1.21, respectively). Intrarenal scRNAseq transcriptomes in patients with AKI-defined cell populations revealed concordant changes in EGF and MCP-1 levels and identified underlying molecular processes associated with loss of EGF expression and gain of CCL2 (encoding MCP-1) expression. CONCLUSION. Urinary EGF and MCP-1 were each independently associated with CKD incidence or progression after cardiac surgery. These markers may serve as noninvasive indicators of tubular damage, supported by tissue transcriptomes and provide opportunity for novel interventions in cardiac surgery. TRIAL REGISTRATION. ClinicalTrials.gov NCT00774137 FUNDING. NIH (R01HL085757 to CRP) funded the TRIBE-AKI Consortium.
Authors
Steven Menez, Wenjun Ju, Rajasree Menon, Dennis G. Moledina, Heather Thiessen Philbrook, Eric McArthur, Yaqi Jia, Wassim Obeid, Sherry G. Mansour, Jay K. Koyner, Michael G. Shlipak, Steven G. Coca, Amit X. Garg, John A. Kellum, Andrew S Bomback, Matthias Kretzler, Chirag R. Parikh
Abstract
Right ventricular (RV) fibrosis is a key feature of maladaptive RV hypertrophy and dysfunction and is associated with poor outcomes in pulmonary hypertension (PH). However, mechanisms and therapeutic strategies to mitigate RV fibrosis remain unrealized. Previously, we identified that cardiac fibroblast α7 nicotinic acetylcholine receptor (α7 nAChR) drives smoking induced RV fibrosis. Here we sought to define the role of α7 nAChR in RV dysfunction and fibrosis in the settings of RV pressure overload as seen in PH. We show that RV tissue from PH patients has increased collagen content and ACh expression. Using experimental rat model of PH, we demonstrate that RV fibrosis and dysfunction are associated with increases in ACh and α7 nAChR expression in the RV but not in the LV. In vitro studies show that α7 nAChR activation leads to an increase in adult ventricular fibroblast proliferation and collagen content mediated by a Ca2+/ epidermal growth factor receptor (EGFR) signaling mechanism. Pharmacological antagonism of nAChR decreases RV collagen content and improves RV function in the PH model. Further, mice lacking α7 nAChR exhibit improved RV diastolic function and have lower RV collagen content in response to persistently increased RV afterload, compared to wild-type controls. These finding indicate that enhanced α7 nAChR signaling is an important mechanism underlying RV fibrosis and dysfunction, and targeted inhibition of α7 nAChR is a novel therapeutic strategy in the setting of increased RV afterload.
Authors
Alexander Vang, Denielli da Silva Gonçalves Bos, Ana Fernandez-Nicolas, Peng Zhang, Alan R. Morrison, Thomas J. Mancini, Richard T. Clements, Iuliia Polina, Michael W. Cypress, Bong Sook Jhun, Edward Hawrot, Ulrike Mende, Jin O-Uchi, Gaurav Choudhary
Abstract
Adipocytes were long considered to be inert components of the bone marrow niche, but both mouse and human models suggest that bone marrow adipose tissue (BMAT) is dynamic and responsive to hormonal and nutrient cues. In this study of healthy volunteers, we investigated how BMAT responds to acute nutrient changes, including analyses of endocrine determinants and paracrine factors from marrow aspirates. Study participants underwent a 10-day high-calorie protocol followed by a 10-day fast. We demonstrate three novel findings: 1) vertebral BMAT increased significantly during both high-calorie feeding and fasting, suggesting that BMAT may have different functions in states of caloric excess compared to caloric deprivation; 2) Ghrelin, which decreased in response to both high-calorie feeding and fasting, was inversely associated with changes in BMAT; 3) In response to high-calorie feeding, resistin levels in the marrow sera, but not the circulation, rose significantly. In addition, TNF-a expression in marrow adipocytes increased with high-calorie feeding and decreased upon fasting. Therefore, high-calorie feeding, but not fasting, induces an immune response in the bone marrow similar to what has been reported in peripheral adipose tissue. Understanding the immunomodulatory regulators in the marrow may provide further insight into the homeostatic function of this unique adipose tissue depot.
Authors
Pouneh K. Fazeli, Miriam A. Bredella, Olga Gisela Pachon-Peña, Wenxiu Zhao, Xun Zhang, Alexander T. Faje, Megi Resulaj, Sai P. Polineni, Tara M. Holmes, Hang Lee, Elizabeth K. O’Donnell, Ormond A. MacDougald, Mark C. Horowitz, Clifford J. Rosen, Anne Klibanski
Abstract
BACKGROUND. Continued androgen receptor (AR) signaling constitutes a key target for treatment in metastatic castration-resistant prostate cancer (CRPC). Studies have identified 11-ketotestosterone (11KT) as a potent AR agonist, but it is unknown if 11KT is present at physiologically-relevant concentrations in CRPC patients to drive AR activation. The goal of this study was to investigate the circulating steroid metabolome including all active androgens in CRPC patients. METHODS. Metastatic CRPC patients (n=29) starting a new line of systemic therapy were included. Sequential plasma samples were obtained for measurement of circulating steroid concentrations by multi-steroid profiling employing liquid chromatography-tandem mass spectrometry. Metastatic tumor biopsy samples were obtained at baseline and subjected to RNA sequencing. RESULTS. 11KT was the most abundant circulating active androgen in 97% of CRPC patients (median 0.39 nmol/L, range: 0.03–2.39 nmol/L), constituting 60% (IQR 43-79%) of the total active androgen (TA) pool. Treatment with glucocorticoids reduced 11KT by 84% (49-89%) and testosterone (T) by 68% (38-79%). Circulating TA concentrations at baseline were associated with a distinct intratumoral gene expression signature comprising AR-regulated genes. CONCLUSIONS. The potent AR agonist 11KT is the predominant circulating active androgen in CRPC patients and, therefore, one of the potential drivers of AR activation in CRPC. Assessment of androgen status should be extended to include 11KT, as current clinical approaches likely underestimate androgen abundance in CRPC patients. Trial registrationNetherlands TRIAL REGISTRATION. NL5625(NTR5732) FUNDING. Daniel den Hoed foundation (Hofland) and Wellcome Trust (Investigator Award WT209492/Z/17/Z, Arlt)
Authors
Gido Snaterse, Lisanne F. van Dessel, Job van Riet, Angela E. Taylor, Michelle van der Vlugt-Daane, Paul Hamberg, Ronald de Wit, Jenny A. Visser, Wiebke Arlt, Martijn P. Lolkema, Johannes Hofland
Abstract
The hypothalamus is a critical regulator of glucose metabolism and is capable of correcting diabetes conditions independently of an effect on energy balance. The small GTPase Rap1 in the forebrain is implicated in high-fat diet (HFD)-induced obesity and glucose imbalance. Here, we report that increasing Rap1 activity selectively in the medial hypothalamus elevated blood glucose without increasing the body weight of HFD-fed mice. In contrast, decreasing hypothalamic Rap1 activity protected mice from diet-induced hyperglycemia but did not prevent weight gain. The remarkable glycemic effect of Rap1 was reproduced when Rap1 was specifically deleted in SF1-positive neurons in the ventromedial hypothalamic nucleus (VMH) known to regulate glucose metabolism. While having no effect on body weight regardless of sex, diet, and age, Rap1 deficiency in the VMH SF1 neurons markedly lowered blood glucose and insulin levels, improved glucose and insulin tolerance, and protected mice against HFD-induced neural leptin resistance and peripheral insulin resistance at the cellular and whole-body levels. Lastly, acute pharmacological inhibition of brain Epac2, a direct activator of Rap1, corrected glucose imbalance in obese mouse models. Our findings uncover the primary role of VMH Rap1 in glycemic control and implicate Rap1 signaling as a potential target for therapeutic intervention in diabetes.
Authors
Kentaro Kaneko, Hsiao-Yun Lin, Yukiko Fu, Pradip K. Saha, Ana B. De la Puente-Gomez, Yong Xu, Kousaku Ohinata, Peter Chen, Alexei Morozov, Makoto Fukuda
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