Altered chaperone–nonmuscle myosin II interactions drive pathogenicity of the UNC45A c.710T>C variant in osteo-oto-hepato-enteric syndrome

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Abstract

The osteo-oto-hepato-enteric (O2HE) syndrome is a severe autosomal recessive disease ascribed to loss-of-function mutations in the Unc-45 myosin chaperone A (UNC45A) gene. The clinical spectrum includes bone fragility, hearing loss, cholestasis, and life-threatening diarrhea associated with microvillus inclusion disease–like enteropathy. Here, we present molecular and functional analysis of the UNC45A c.710T>C (p.Leu237Pro) missense variant, which revealed a unique pathogenicity compared with other genetic variants causing UNC45A deficiency. The UNC45A p.Leu237Pro mutant retained chaperone activity, prevented myosin aggregation, and supported proper nonmuscle myosin II (NMII) filament formation in patient fibroblasts and human osteosarcoma (U2OS) cells. However, the mutant formed atypically stable oligomers and prevented chaperone-myosin complex dissociation, thereby inhibiting NMII functions. Similar to biallelic UNC45A deficiency, this resulted in impaired intracellular trafficking, defective recycling, and abnormal retention of transferrin at various endocytic sites. In particular, coexpression of wild-type protein attenuated the pathogenic effects of the variant by inhibiting excessive oligomer formation. Our results elucidate the pathogenic mechanisms and recessive characteristics of this variant and may aid in the development of targeted therapies.

Authors

Stephanie Waich, Karin Kreidl, Julia Vodopiutz, Arzu Meltem Demir, Adam R. Pollio, Vojtěch Dostál, Kristian Pfaller, Marianna Parlato, Nadine Cerf-Bensussan, Rüdiger Adam, Georg F. Vogel, Holm H. Uhlig, Frank M. Ruemmele, Thomas Müller, Michael W. Hess, Andreas R. Janecke, Lukas A. Huber, Taras Valovka

Map2k6 is a potent genetic modifier of arterial rupture in vascular Ehlers-Danlos syndrome mice

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Abstract

Aortic dissection or rupture is a major cause of mortality in vascular Ehlers-Danlos syndrome (vEDS), a connective tissue disorder caused by heterozygous mutations in the collagen type III alpha 1 chain (COL3A1) gene. C57BL6/J (BL6) mice carrying the Col3a1G938D/+ mutation recapitulate the vEDS vascular phenotype and die suddenly of aortic rupture/dissection. However, 129S6/SvEvTac (referred to here as 129) mice expressing the same Col3a1G938D/+ mutation show near-complete lifelong protection from vascular rupture. To identify genetic modifiers of vascular risk in vEDS, we performed genome-wide genotyping of intercrossed BL6/129 vEDS mice stratified by survival and identified a significant protective locus encompassing a variant in Map2k6, encoding mitogen-activated protein kinase kinase 6 (M2K6), a p38-activating kinase. Genetic ablation of Map2k6 rendered previously protected 129 vEDS mice susceptible to aortic rupture, in association with reduced protein phosphatase 1 activity and increased PKC and ERK phosphorylation. Accelerated vascular rupture in vEDS mice treated with a pharmacological inhibitor of p38 was rescued by concomitant ERK antagonism, supporting an opposing role for ERK and p38 in the modification of aortic rupture risk in vEDS. These results suggest that pharmacologic strategies aimed at mimicking the effect of this natural protective pathway may attenuate aortic rupture risk in vEDS.

Authors

Caitlin J. Bowen, Rebecca Sorber, Juan Francisco Calderón Giadrosic, Jefferson J. Doyle, Graham Rykiel, Zachary Burger, Xiaoyan Zhang, Wendy A. Espinoza Camejo, Nicole Anderson, Simone Sabnis, Chiara Bellini, Elena Gallo MacFarlane, Harry C. Dietz

ROCK1 promotes B cell differentiation and proteostasis under stress through the heme-regulated proteins, BACH2 and HRI

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Abstract

The mechanisms utilized by differentiating B cells to withstand highly damaging conditions generated during severe infections, like the massive hemolysis that accompanies malaria, are poorly understood. Here, we demonstrate that ROCK1 regulates B cell differentiation in hostile environments replete with pathogen-associated molecular patterns (PAMPs) and high levels of heme by controlling 2 key heme-regulated molecules, BACH2 and heme-regulated eIF2α kinase (HRI). ROCK1 phosphorylates BACH2 and protects it from heme-driven degradation. As B cells differentiate, furthermore, ROCK1 restrains their pro-inflammatory potential and helps them handle the heightened stress imparted by the presence of PAMPs and heme by controlling HRI, a key regulator of the integrated stress response and cytosolic proteotoxicity. ROCK1 controls the interplay of HRI with HSP90 and limits the recruitment of HRI and HSP90 to unique p62/SQSTM1 complexes that also contain critical kinases like mTOR complex 1 and TBK1, and proteins involved in RNA metabolism, oxidative damage, and proteostasis like TDP-43. Thus, ROCK1 helps B cells cope with intense pathogen-driven destruction by coordinating the activity of key controllers of B cell differentiation and stress responses. These ROCK1-dependent mechanisms may be widely employed by cells to handle severe environmental stresses, and these findings may be relevant for immune-mediated and age-related neurodegenerative disorders.

Authors

Juan Rivera-Correa, Sanjay Gupta, Edd Ricker, Danny Flores-Castro, Daniel Jenkins, Stephen Vulcano, Swati P. Phalke, Tania Pannellini, Matthew M. Miele, Zhuoning Li, Nahuel Zamponi, Young-Bum Kim, Yurii Chinenov, Eugenia Giannopoulou, Leandro Cerchietti, Alessandra B. Pernis

Aerobic exercise prevents renal osteodystrophy via irisin-activated osteoblasts

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Abstract

Renal osteodystrophy is commonly seen in patients with chronic kidney disease (CKD) due to disrupted mineral homeostasis. Given the impaired renal function in these patients, common antiresorptive agents, including bisphosphonates, must be used with caution or even contraindicated. Therefore, an alternative therapy without renal burden to combat renal osteodystrophy is urgently needed. Here, we report that clinically relevant aerobic exercise significantly prevents high-turnover renal osteodystrophy in CKD mice and patients with CKD without compromising renal function. Mechanistically, 4-week aerobic exercise in CKD mice increased expression of skeletal muscle PPARγ coactivator-1α (PGC-1α) and circulating irisin. Both exercise and irisin administration significantly activated osteoblasts, but not osteoclasts, via integrin αvβ5, thereby conferring bone quality benefits. Removal of irisin-influenced thermogenic adipose tissues or genetic ablation of uncoupling protein 1 did not alter the irisin-conferred antiosteodystrophy effect. Importantly, in a pilot clinical study, 12-week aerobic exercise in patients with high-grade CKD significantly increased circulating irisin and prevented osteodystrophy progression, without detectable renal burden. The combination of irisin and current antiresorptive agents effectively rescued renal osteodystrophy in mice. Our work provides mechanistic insights into the role of exercise and irisin in renal osteodystrophy, and it highlights a clinically relevant, low-cost, kidney-friendly therapy for patients with this devastating disease.

Authors

Meng Wu, Huilan Li, Xiaoting Sun, Rongrong Zhong, Linli Cai, Ruibo Chen, Madiya Madeniyet, Kana Ren, Zhen Peng, Yujie Yang, Weiqin Chen, Yanling Tu, Miaoxin Lai, Jinxiu Deng, Yuting Wu, Shumin Zhao, Qingyan Ruan, Mei Rao, Sisi Xie, Ying Ye, Jianxin Wan

A single-cell atlas of normal and KRAS^G12D-malformed lymphatic vessels

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Abstract

Somatic activating mutations in KRAS can cause complex lymphatic anomalies (CLAs). However, the specific processes that drive KRAS-mediated CLAs have yet to be fully elucidated. Here, we used single-cell RNA sequencing to construct an atlas of normal and KrasG12D-malformed lymphatic vessels. We identified 6 subtypes of lymphatic endothelial cells (LECs) in the lungs of adult wild-type mice (Ptx3, capillary, collecting, valve, mixed, and proliferating). To determine when the LEC subtypes were specified during development, we integrated our data with data from 4 stages of development. We found that proliferating and Ptx3 LECs were prevalent during early lymphatic development and that collecting and valve LECs emerged later in development. Additionally, we discovered that the proportion of Ptx3 LECs decreased as the lymphatic network matured but remained high in KrasG12D mice. We also observed that the proportion of collecting and valve LECs was lower in KrasG12D mice than in wild-type mice. Last, we found that immature lymphatic vessels in young mice were more sensitive to the pathologic effects of KrasG12D than mature lymphatic vessels in older mice. Together, our results expand the current model for the development of the lymphatic system and suggest that KRAS mutations impair the maturation of lymphatic vessels.

Authors

Lorenzo M. Fernandes, Danielle Griswold-Wheeler, Jeffrey D. Tresemer, Angelica Vallejo, Neda Vishlaghi, Benjamin Levi, Abigail Shapiro, Joshua P. Scallan, Michael T. Dellinger

The AURKA inhibitor alters the immune microenvironment and enhances targeting B7-H3 immunotherapy in glioblastoma

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Abstract

Glioblastoma (GBM) is one of the most lethal adult brain tumors with limited effective therapeutic options. Immunotherapy targeting B7-H3 (CD276) has shown promising efficacy in the treatment of gliomas. However, the response to this treatment varies among glioma patients due to individual differences. It’s necessary to find an effective strategy to improve the efficacy of targeting B7-H3 immunotherapy for nonresponders. In this study, we demonstrated a strong correlation between aurora kinase A (AURKA) and CD276 expression in glioma tissue samples. Additionally, both AURKA knockdown and overexpression resulted in parallel changes in B7-H3 expression levels in glioma cells. Mechanistically, AURKA elevated B7-H3 expression by promoting epidermal growth factor receptor (EGFR) phosphorylation, which was validated in glioma cell lines and primary GBM cells. What’s more, the combination of AURKA inhibitor (alisertib) and anti–B7-H3 antibody markedly reduced tumor size and promoted CD8+ T cell infiltration and activation in mouse orthotopic syngeneic glioma models. To our knowledge, this study is the first to demonstrate AURKA-mediated B7-H3 upregulation in glioma cells; moreover, it proposes a promising therapeutic strategy combining the AURKA inhibitor alisertib with B7-H3–specific blocking mAbs.

Authors

Jinqiu Liu, Yuxuan Deng, Zhuonan Pu, Yazhou Miao, Zhaonian Hao, Herui Wang, Shaodong Zhang, Hanjie Liu, Jiejun Wang, Yifan Lv, Boyi Hu, Hong Wan, Zhengping Zhuang, Tai Sun, Shuyu Hao, Nan Ji, Jie Feng

Fibroblast growth factor–inducible 14 regulates satellite cell self-renewal and expansion during skeletal muscle repair

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Abstract

Skeletal muscle regeneration in adults is predominantly driven by satellite cells. Loss of satellite cell pool and function leads to skeletal muscle wasting in many conditions and disease states. Here, we demonstrate that the levels of fibroblast growth factor–inducible 14 (Fn14) were increased in satellite cells after muscle injury. Conditional ablation of Fn14 in Pax7-expressing satellite cells drastically reduced their expansion and skeletal muscle regeneration following injury. Fn14 was required for satellite cell self-renewal and proliferation as well as to prevent precocious differentiation. Targeted deletion of Fn14 inhibited Notch signaling but led to the spurious activation of STAT3 signaling in regenerating skeletal muscle and in cultured muscle progenitor cells. Silencing of STAT3 improved proliferation and inhibited premature differentiation of Fn14-deficient satellite cells. Furthermore, conditional ablation of Fn14 in satellite cells exacerbated myopathy in the mdx mouse model of Duchenne muscular dystrophy (DMD), whereas its overexpression improved the engraftment of exogenous muscle progenitor cells into the dystrophic muscle of mdx mice. Altogether, our study highlights the crucial role of Fn14 in the regulation of satellite cell fate and function and suggests that Fn14 can be a potential molecular target to improve muscle regeneration in muscular disorders.

Authors

Meiricris Tomaz da Silva, Aniket S. Joshi, Ashok Kumar

Orchestrated response from heterogenous fibroblast subsets contributes to repair from surgery-induced stress after airway reconstruction

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Abstract

Surgery of the tracheobronchial tree carries high morbidity, with over half of the complications occurring at the anastomosis. Although fibroblasts are crucial in airway wound healing, the underlying cellular and molecular mechanisms in airway reconstruction remain unknown. We hypothesized that airway reconstruction initiates a surgery-induced stress (SIS) response, altering fibroblast communication within airway tissues. Using single-cell RNA-Seq, we analyzed native and reconstructed airways and identified 5 fibroblast subpopulations, each with distinct spatial distributions across anastomotic, submucosal, perichondrial, and paratracheal areas. During homeostasis, adventitial and airway fibroblasts (Adventitial-Fb and Airway-Fb, respectively) maintained tissue structure and created cellular niches by regulating ECM turnover. Under SIS, perichondrial fibroblasts (PC-Fb) exhibited chondroprogenitor-like gene signatures, and immune-recruiting fibroblasts (IR-Fb) facilitated cell infiltration. Cthrc1-activated fibroblasts (Cthrc1+ Fb), mainly derived from Adventitial-Fb, primarily contributed to fibrotic scar formation and collagen production, mediated by TGF-β. Furthermore, repeated SIS created an imbalance in fibroblast states favoring emergence of CTHRC1+ Fb and leading to impaired fibroblasts–basal cell crosstalk. Collectively, these data identify PC, IR, and Cthrc1+ Fb as a signaling hub, with SIS emerging as a mechanism initiating airway remodeling after reconstruction that, if not controlled, may lead to complications such as stenosis or anastomotic breakdown.

Authors

Jazmin Calyeca, Zakarie Hussein, Zheng Hong Tan, Lumei Liu, Sayali Dharmadhikari, Kimberly M. Shontz, Tatyana A. Vetter, Christopher K. Breuer, Susan D. Reynolds, Tendy Chiang

Neutrophils initiate proinflammatory immune responses in early endometriosis lesion development

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Abstract

Endometriosis is a chronic gynecological disease that affects 1 in 10 reproductive-aged women. Most studies investigate established disease; however, the initiation and early events in endometriotic lesion development remain poorly understood. Our study used neutrophils from human menstrual effluent from patients with and without endometriosis for immunophenotyping, and it used a mouse model of endometriosis and a mouse endometriosis cell line to determine the role of neutrophils in the initiating events of endometriosis, including attachment and survival of minced endometrial pieces. In menstrual effluent from women with endometriosis, the ratios of aged and proangiogenic neutrophils increased compared with controls, indicating a potentially permissive proinflammatory microenvironment. In our endometriosis mouse model, knocking down neutrophil recruitment with α-CXCR2 into the peritoneum decreased endometrial tissue adhesion — supported by decreased levels of myeloperoxidase and neutrophil elastase in both developing lesions and peritoneal fluid. Fibrinogen was identified as the preferred substrate for endometrial cell adhesion in an in vitro adhesion assay and in developing lesions in vivo. Together, aged and proangiogenic neutrophils and their secretions likely promote attachment and formation of endometriotic lesions by releasing neutrophil extracellular traps and upregulating fibrinogen expression as a provisional matrix to establish attachment and survival in the development of endometriosis lesions.

Authors

Taylor R. Wilson, Kurt R. Peterson, Stephanie A. Morris, Damaris Kuhnell, Susan Kasper, Katherine A. Burns

Impaired axonal transport contributes to neurodegeneration in a Cre-inducible mouse model of myocilin-associated glaucoma

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Abstract

Elevation of intraocular pressure (IOP) due to trabecular meshwork (TM) dysfunction, leading to neurodegeneration, is the pathological hallmark of primary open-angle glaucoma (POAG). Impaired axonal transport is an early and critical feature of glaucomatous neurodegeneration. However, a robust mouse model that accurately replicates these human POAG features has been lacking. We report the development and characterization of a new Cre-inducible mouse model expressing a DsRed-tagged Y437H mutant of human myocilin (Tg.CreMYOCY437H). A single intravitreal injection of HAd5-Cre induced selective MYOC expression in the TM, causing TM dysfunction, reducing the outflow facility, and progressively elevating IOP in Tg.CreMYOCY437H mice. Sustained IOP elevation resulted in significant loss of retinal ganglion cells (RGCs) and progressive axonal degeneration in Cre-induced Tg.CreMYOCY437H mice. Notably, impaired anterograde axonal transport was observed at the optic nerve head before RGC degeneration, independent of age, indicating that impaired axonal transport contributes to RGC degeneration in Tg.CreMYOCY437H mice. In contrast, axonal transport remained intact in ocular hypertensive mice injected with microbeads, despite significant RGC loss. Our findings indicate that Cre-inducible Tg.CreMYOCY437H mice replicate all glaucoma phenotypes, providing an ideal model for studying early events of TM dysfunction and neuronal loss in POAG.

Authors

Balasankara Reddy Kaipa, Ramesh Kasetti, Yogapriya Sundaresan, Linya Li, Sam Yacoub, J. Cameron Millar, William Cho, Dorota Skowronska-Krawczyk, Prabhavathi Maddineni, Krzysztof Palczewski, Gulab S. Zode