Khatri et al. report that JAK-STAT activation in airways following human lung transplantation contributes to upregulation of MHC-I in donor basal cells and alloimmune cytotoxic T cell–mediated basal cell death. The cover image shows a bronchiole with epithelial cell loss accompanied by peribronchiolar fibrosis, a defining histologic feature in bronchiolitis obliterans, a form of chronic lung allograft dysfunction after lung transplant.
BACKGROUND. Due to their immunoregulatory and tissue regenerative features, mesenchymal stromal cells (MSCs) are a promising novel tool for the management of ulcerative proctitis (UP). Here we report on a phase IIa clinical study to evaluate the impact of local MSC therapy in UP. METHODS. Thirteen refractory UP patients, with endoscopic Mayo score (EMS) 2 or 3, were included. Seven patients received 20-40 x 106 allogeneic MSCs (cohort 1), while six patients received 40-80 x 106 MSCs (cohort 2). Adverse events (AEs) were assessed at baseline and week 2, 6, 12, and 24. Clinical, endoscopic, and biochemical parameters were assessed at baseline, week 2 and 6. Furthermore, we evaluated the engraftment of MSCs, presence of donor-specific human leukocyte antigen (HLA) antibodies (DSAs), and we determined the impact of MSC therapy on the local immune compartment. RESULTS. No serious AEs were observed. The clinical Mayo score was significantly improved at week 2 and 6, and the EMS was significantly improved at week 6, compared to baseline. At week 6, donor MSCs were still detectable in rectum biopsies of 4/9 patients and DSAs against both HLA-class I and -class II were found. Mass cytometry showed a reduction of activated CD8+ T cells and CD16+ monocytes and an enrichment in mononuclear phagocytes and natural killer cells in biopsies after local MSC therapy. CONCLUSION. Local administration of allogeneic MSCs is safe, tolerable, and feasible for treatment of refractory UP and shows encouraging signs of clinical efficacy and modulation of local immune responses. This sets the stage for larger clinical trials. TRIAL REGISTRATION. clinicaltrialsregister.eu, EudraCT: 2017-003524-75, Dutch Trial register: NTR7205. FUNDING. ECCO grant 2020.
Laura F. Ouboter, Marieke C. Barnhoorn, Hein W. Verspaget, Leonie Plug, Emma S. Pool, Karoly Szuhai, Lukas J.A.C. Hawinkels, Melissa van Pel, Jaap Jan Zwaginga, Dave Roelen, Frits Koning, M. Fernanda Pascutti, Andrea van der Meulen - de Jong
BACKGROUND. Longitudinal investigations of murine acute kidney injury (AKI) suggest that injury and inflammation may persist long after the initial insult. However, the evolution of these processes and their prognostic values are unknown in patients with AKI. METHODS. In a prospective cohort of 656 participants hospitalized with AKI, we measured seven urine and two plasma biomarkers of kidney injury, inflammation, and tubular health at multiple timepoints from the diagnosis to 12 months after AKI. We used linear mixed-effect models to estimate biomarker changes over time, and used Cox proportional hazard regressions to determine their associations with a composite outcome of CKD incidence and progression. We compared the gene expression kinetics of biomarkers in murine models of repair and atrophy after ischemic reperfusion injury (IRI). RESULTS. After 4.3 years, 106 and 52 participants developed incident CKD and CKD progression, respectively. Each standard deviation increases in the change of urine KIM-1, MCP-1 and plasma TNFR1 from baseline to 12 months was associated with 2-3-fold increased risk for CKD, while the increase in urine UMOD was associated with 40% reduced risk for CKD. The trajectories of these biological processes were associated with progression to kidney atrophy in mice after IRI. CONCLUSION. Sustained tissue injury and inflammation, and slower restoration of tubular health are associated with higher risk of kidney disease progression. Further investigation into these ongoing biological processes may help understand and prevent the AKI-to-CKD transition. FUNDING. NIH and NIDDK (grants U01DK082223, U01DK082185, U01DK082192, U01DK082183, R01DK098233, R01DK101507, R01DK114014, K23DK100468, R03DK111881, K01DK120783, and R01DK093771).
Yumeng Wen, Leyuan Xu, Isabel A. Melchinger, Heather Thiessen-Philbrook, Dennis G. Moledina, Steven G. Coca, Chi-yuan Hsu, Alan S. Go, Kathleen D. Liu, Edward D. Siew, T. Alp Ikizler, Vernon M. Chinchilli, James S. Kaufman, Paul L. Kimmel, Jonathan Himmelfarb, Lloyd G. Cantley, Chirag R. Parikh
Phosphoinositides (PI) are membrane lipids that regulate signal transduction and vesicular trafficking. X-linked centronuclear myopathy (XLCNM), also called myotubular myopathy, results from loss-of-function mutations in the Mtm1 gene, which encodes the myotubularin phosphatidylinositol 3-phosphate (PtdIns3P) lipid phosphatase. No therapy for this disease is currently available. Previous studies showed that loss of expression of the class II phosphoinositide 3-kinase (PI3K) PI3K-C2β protein improved the phenotypes of a XLCNM mouse model. PI3Ks are well known to have extensive scaffolding functions and the importance of the catalytic activity of this PI3K for rescue remains unclear. Here, using PI3K-C2β kinase-dead mice, we show that the selective inactivation of PI3K-C2β kinase activity is sufficient to fully prevent muscle atrophy and weakness, histopathology, and sarcomere and triad disorganization in Mtm1 knockout mice. This rescue correlates with normalization of PtdIns3P level and mTORC1 activity, a key regulator of protein synthesis and autophagy. Conversely, lack of PI3K-C2β kinase activity did not rescue the histopathology of the BIN1 autosomal centronuclear myopathy mouse model. Overall, these findings support the development of specific PI3K-C2β kinase inhibitors to cure myotubular myopathy.
Xènia Massana-Muñoz, Marie Goret, Vasugi Nattarayan, David Reiss, Christine Kretz, Gaetan Chicanne, Bernard Payrastre, Bart Vanhaesebroeck, Jocelyn Laporte
Gain-of-function mutations in the housekeeping gene GARS1, which lead to the expression of toxic versions of glycyl-tRNA synthetase (GlyRS), cause the selective motor and sensory pathology characterising Charcot-Marie-Tooth disease (CMT). Aberrant interactions between GlyRS mutants and different proteins, including neurotrophin receptor TrkB, underlie CMT type 2D (CMT2D); however, our pathomechanistic understanding of this untreatable peripheral neuropathy remains incomplete. Through intravital imaging of the sciatic nerve, we show that CMT2D mice display early and persistent disturbances in axonal transport of neurotrophin-containing signalling endosomes in vivo. We discovered that BDNF-TrkB impairments correlate with transport disruption and overall CMT2D neuropathology, and that inhibition of this pathway at the nerve-muscle interface perturbs endosome transport in wild-type axons. Accordingly, supplementation of muscles with BDNF, but not other neurotrophins, completely restores physiological axonal transport in neuropathic mice. Together, these findings suggest that selectively targeting muscles with BDNF-boosting therapies could represent a viable therapeutic strategy for CMT2D.
James N. Sleigh, David Villarroel-Campos, Sunaina Surana, Tahmina Wickenden, Yao Tong, Rebecca L. Simkin, Jose Norberto S. Vargas, Elena R. Rhymes, Andrew P. Tosolini, Steven J. West, Qian Zhang, Xiang-Lei Yang, Giampietro Schiavo
Tuberous Sclerosis Complex (TSC) is characterized by multi-system low-grade neoplasia involving the lung, kidneys, brain, and heart. Lymphangioleiomyomatosis (LAM) is a progressive pulmonary disease affecting almost exclusively women. TSC and LAM are both caused by mutations in TSC1 and TSC2 that results in mTORC1 hyperactivation. Here, we report that single-cell RNA sequencing of LAM lungs identified activation of genes in the sphingolipid biosynthesis pathway. Accordingly, the expression of acid ceramidase (ASAH1) and dihydroceramide desaturase (DEGS1), key enzymes controlling sphingolipid and ceramide metabolism, was significantly increased in TSC2-null cells. TSC2 negatively regulated the biosynthesis of tumorigenic sphingolipids, and suppression of ASAH1 by shRNA or the inhibitor ARN14976 (17a) resulted in markedly decreased TSC2-null cell viability. In vivo, 17a significantly decreased the growth of TSC2-null cell derived mouse xenografts and short-term lung colonization by TSC2-null cells. Combined rapamycin and 17a treatment synergistically inhibited renal cystadenoma growth in Tsc2+/- mice, consistent with increased ASAH1 expression and activity being rapamycin insensitive. Collectively, the present study identifies rapamycin-insensitive ASAH1 upregulation in TSC2-null cells and tumors and provides evidence that targeting aberrant sphingolipid biosynthesis pathways has potential therapeutic value in mTORC1-hyperactive neoplasms including TSC and LAM.
Aristotelis Astrinidis, Chenggang Li, Erik Y. Zhang, Xueheng Zhao, Shuyang Zhao, Minzhe Guo, Tasnim Olatoke, Ushodaya Mattam, Rong Huang, Alan Zhang, Lori Pitstick, Elizabeth J. Kopras, Nishant Gupta, Roman A. Jandarov, Eric P. Smith, Elizabeth Fugate, Diana Lindquist, Maciej M. Markiewski, Magdalena Karbowniczek, Kathryn A. Wikenheiser-Brokamp, Kenneth D. Setchell, Francis X. McCormack, Yan Xu, Jane Yu
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