Kidney-specific claudin-2 deficiency leads to medullary nephrocalcinosis in mice

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Abstract

Deposits of hydroxyapatite called Randall's plaques are found in the renal papilla of calcium oxalate kidney stone formers and likely serve as the nidus for stone formation, but their pathogenesis is unknown. Claudin-2 is a paracellular ion channel that mediates calcium reabsorption in the renal proximal tubule. To investigate the role of renal claudin-2, we generated kidney tubule-specific claudin-2 conditional knockout mice (KS-Cldn2 KO). KS-Cldn2 KO mice exhibited transient hypercalciuria in early life. Normalization of urine calcium was accompanied by a compensatory increase in expression and function of renal tubule calcium transporters, including in the thick ascending limb. Despite normocalciuria, KS-Cldn2 KO mice developed papillary hydroxyapatite deposits, beginning at 6 months of age, that resembled Randall's plaques and tubule plugs. Bulk chemical tissue analysis and laser ablation-inductively coupled plasma mass spectrometry revealed a gradient of intrarenal calcium concentration along the corticomedullary axis in normal mice, that was accentuated in KS-Cldn2 KO mice. Our findings provide evidence for the “vas washdown” hypothesis for Randall's plaque formation, and identify the corticomedullary calcium gradient as a target for therapies to prevent kidney stone disease.

Authors

Christine V. Behm, Duuamene Nyimanu, Ony Araujo Galdino, Sadhana Kanoo, Young Chul Kim, Natalia Lopez, Helen Goodluck, Peter S. Rowe, Andrew P. Evan, André J. Sommer, Matthew N. Barr, Tracy Punshon, Volker Vallon, Brian P. Jackson, James C. Williams Jr., Alan S.L. Yu

S100a9 lactylation triggers neutrophil trafficking and cardiac inflammation in myocardial ischemia/reperfusion injury

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Abstract

Lactylation, a post-translational modification derived from glycolysis, plays a pivotal role in ischemic heart diseases. Neutrophils are predominantly glycolytic cells that trigger intensive inflammation of myocardial ischemia reperfusion (MI/R). However, whether lactylation regulates neutrophil function during MI/R remains unknown. Employing lactyl proteomics analysis, S100a9 was lactylated at lysine 26 (S100a9K26la) in neutrophils, with elevated levels observed in both acute myocardial infarction (AMI) patients and MI/R model mice. S100a9K26la was demonstrated driving the development of MI/R using mutant knock-in mice. Mechanistically, lactylated S100a9 translocated to the nucleus of neutrophils, where it binded to the promoters of migration-related genes, thereby enhancing their transcription as a co-activator and promoting neutrophil migration and cardiac recruitment. Additionally, lactylated S100a9 was released during NETosis, leading to cardiomyocyte death by disrupting mitochondrial function. The enzyme dihydrolipoyllysine-residue acetyltransferase (DLAT) was identified as the lactyltransferase facilitating neutrophil S100a9K26la post-MI/R, a process that could be restrained by α-lipoic acid. Consistently, targeting DLAT/S100a9K26la axis suppressed neutrophil burden and improved cardiac function post-MI/R. In patients with AMI, elevated S100a9K26la levels in plasma were positively correlated with cardiac death. These findings highlight S100a9 lactylation as a potential therapeutic target for MI/R and as a promising biomarker for evaluating poor prognosis of MI/R.

Authors

Xiaoqi Wang, Xiangyu Yan, Ge Mang, Yujia Chen, Shuang Liu, Jiayu Sui, Zhonghua Tong, Penghe Wang, Jingxuan Cui, Qiannan Yang, Yafei Zhang, Dongni Wang, Ping Sun, Weijun Song, Zexi Jin, Ming Shi, Peng Zhao, Jia Yang, Mingyang Liu, Naixin Wang, Tao Chen, Yong Ji, Bo Yu, Maomao Zhang

Endoglucanase-2 (Eng2), a shared immunodominant antigen in dimorphic fungi that elicits immunity during infection

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Abstract

Herein, we describe a shared surface and cell wall protein, Endoglucanase 2 (Eng2), expressed on the etiological agents that cause the endemic systemic mycoses of North America – Blastomyces, Coccidioides and Histoplasma. We demonstrate that despite sequence variation of the protein across these related fungi, exposure to Eng2 vaccinates and protects inbred and humanized HLA-DR4 strains of mice against lethal experimental infections with these fungi by eliciting adaptive immunity mediated by CD4 T cells. We also show that CD4 T cell precursors against Eng2 are detectable in naïve individuals and that patients who have recovered from these infections evince a memory and recall CD4 T cell response to Eng2 and its immunodominant epitopes that we have mapped. We create and catalogue new tools and information such as immunodominant peptide epitopes of Eng2 from each fungus recognized by inbred mice and human subjects and we engineer peptide-MHC II tetramers for tracking T cells in inbred and HLA-DR4 humanized mice that will be useful for those who study these infections in mice and humans. Lastly, because most patients demonstrate memory and recall responses against Eng2, our work offers new tools for diagnosis of this collection of infectious diseases across North America.

Authors

Uju J. Okaa, Cleison Ledesma Taira, Lucas dos Santos Dias, Hannah Dobson, Gregory C. Kujoth, Althea Campuzano, E.Jane Homan, George R. Thompson, Chiung-Yu Hung, George S. Deepe, Marcel Wüthrich, Bruce S. Klein

CDKL1 variants affecting ciliary formation predispose to thoracic aortic aneurysm and dissection

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Abstract

Genetic factors are fundamental in the etiology of thoracic aortic aneurysm and dissection (TAAD), but the genetic cause is detected in only about 30% of cases. To define unreported TAAD-associated sequence variants, exome and gene panel sequencing was performed in 323 patients. We identified heterozygous CDKL1 variants [c.427T>C p.(Cys143Arg), c.617C>T p.(Ser206Leu), and c.404C>T p.(Thr135Met)] in 6 patients from 3 families with TAAD-spectrum disorders. CDKL1 encodes a protein kinase involved in ciliary biology. Amino acid substitutions were predicted to affect CDKL1 catalytic activity or protein binding properties. CDKL1 was expressed in vascular smooth muscle cells in normal and diseased human aortic wall tissue. Cdkl1 knockdown and transient knockout in zebrafish resulted in intersomitic vessel (ISV) malformations and aortic dilation. Co-injection of human CDKL1wildtype, but not CDKL1Cys143Arg and CDKL1Ser206Leu RNA, rescued ISV malformations. All variants affected CDKL1 kinase function and profiling data, and altered protein-protein binding properties, particularily with ciliary transport molecules. Expression of CDKL1 variants in heterologeous cells interfered with cilia formation and length, CDKL1 localization, and p38-MAPK and Vegf signaling. Our data suggest a role of CDKL1 variants in the pathogenesis of TAAD-spectrum disorders. The association between primary cilia dysregulation and TAAD expands our knowledge of the underlying molecular pathophysiology.

Authors

Theresa Nauth, Melanie Philipp, Sina Renner, Martin D. Burkhalter, Helke Schüler, Ceren Saygi, Kristian Händler, Bente Siebels, Alice Busch, Thomas Mair, Verena Rickassel, Sophia Deden, Konstantin Hoffer, Jakob Olfe, Thomas S. Mir, Yskert von Kodolitsch, Evaldas Girdauskas, Meike Rybczynski, Malte Kriegs, Hannah Voß, Thomas Sauvigny, Malte Spielmann, Malik Alawi, Susanne Krasemann, Christian Kubisch, Till J. Demal, Georg Rosenberger

The cell-type-specific genetic architecture of chronic pain in brain and dorsal root ganglia

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Abstract

Chronic pain is a complex clinical problem comprising multiple conditions that may share a common genetic profile. Genome-wide association studies (GWAS) have identified many risk loci whose cell-type context remains unclear. Here, we integrated GWAS data on chronic pain (N = 1,235,695) with single-cell RNA sequencing (scRNA-seq) data from human brain and dorsal root ganglia (hDRG), and single-cell chromatin accessibility data from human brain and mouse dorsal horn. Pain-associated variants were enriched in glutamatergic neurons; mainly in prefrontal cortex, hippocampal CA1-3, and amygdala. In hDRG, the hPEP.TRPV1/A1.2 neuronal subtype showed robust enrichment. Chromatin accessibility analyses revealed variant enrichment in excitatory and inhibitory neocortical neurons in brain and in midventral neurons and oligodendrocyte precursor cells in the mouse dorsal horn. Gene-level heritability in the brain highlighted roles for kinase activity, GABAergic synapses, axon guidance, and neuron projection development. In hDRG, implicated genes related to glutamatergic signaling and neuronal projection. In cervical DRG of patients with acute or chronic pain (N = 12), scRNA-seq data from neuronal or non-neuronal cells were enriched for chronic pain-associated genes (e.g., EFNB2, GABBR1, NCAM1, SCN11A). This cell-type-specific genetic architecture of chronic pain across central and peripheral nervous system circuits provides a foundation for targeted translational research.

Authors

Sylvanus Toikumo, Marc Parisien, Michael J. Leone, Chaitanya Srinivasan, Huasheng Yu, Asta Arendt-Tranholm, Úrzula Franco-Enzástiga, Christoph Hofstetter, Michele Curatolo, Wenqin Luo, Andreas R. Pfenning, Rebecca P. Seal, Rachel L. Kember, Theodore J. Price, Luda Diatchenko, Stephen G. Waxman, Henry R. Kranzler

IL-17-producing γδ T cells in the tumor microenvironment promote radioresistance in mice

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Abstract

The immunosuppressive tumor microenvironment (TME) drives radioresistance, but the role of γδ T cells in regulating radiosensitivity remains incompletely understood. In this study, we found that γδ T cell infiltration in the TME substantially increased after radiotherapy and contributed to radioresistance. Depletion of γδ T cells enhanced radiosensitivity. Single-cell RNA sequencing revealed that γδ T cells in the post-radiotherapy TME were characterized by the expression of Zbtb16, Il23r, and Il17a, and served as the primary source of IL-17A. These γδ T cells promoted radioresistance by recruiting myeloid-derived suppressor cells and suppressing T cell activation. Mechanistically, radiotherapy-induced tumor cell-derived microparticles containing dsDNA activated the cGAS-STING/NF-κB signaling pathway in macrophages, upregulating the expression of the chemokine CCL20, which was critical for γδ T cell recruitment. Targeting γδ T cells and IL-17A enhanced radiosensitivity and improved the efficacy of radiotherapy combined with anti-PD-1 immunotherapy, providing potential therapeutic strategies to overcome radioresistance.

Authors

Yue Deng, Xixi Liu, Xiao Yang, Wenwen Wei, Jiacheng Wang, Zheng Yang, Yajie Sun, Yan Hu, Haibo Zhang, Yijun Wang, Zhanjie Zhang, Lu Wen, Fang Huang, Kunyu Yang, Chao Wan

Defective Notch1 signaling in endothelial cells drives pathogenesis in a mouse model of Adams-Oliver Syndrome

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Abstract

Adams-Oliver Syndrome (AOS) is a rare congenital disorder characterized by scalp, limb, and cardiovascular defects. While variants in the NOTCH1 receptor, DLL4 ligand, and RBPJ transcription factor have been implicated in AOS, the driving tissue types and molecular mechanisms by which these variants cause pathogenesis are unknown. Here, we used quantitative binding assays to show that AOS-associated RBPJ missense variants compromise DNA binding but not cofactor binding. These findings suggest that AOS-associated RBPJ variants do not function as loss-of-function alleles but instead act as dominant-negative proteins that sequester cofactors from DNA. Consistent with this idea, mice carrying an AOS-associated Rbpj allele develop dominant phenotypes that include increased lethality and cardiovascular defects in a Notch1 heterozygous background, whereas Notch1 and Rbpj compound heterozygous null alleles are well-tolerated. To facilitate studies into the tissues driving AOS pathogenesis, we employed conditional genetics to isolate the contribution of the vascular endothelium to the development of AOS-like phenotypes. Importantly, our studies show that expression of the Rbpj AOS allele in endothelial cells is both necessary and sufficient to cause lethality and cardiovascular defects. These data establish that reduced Notch1 signaling in the vasculature is a key driver of pathogenesis in this AOS mouse model.

Authors

Alyssa F. Solano, Kristina Preusse, Brittany Cain, Rebecca Hotz, Parthav Gavini, Zhenyu Yuan, Benjamin Bowen, Gabrielle Maco, Hope Neal, Ellen K. Gagliani, Christopher Ahn, Hee-Woong Lim, Laura Southgate, Rhett A. Kovall, Raphael Kopan, Brian Gebelein

BAF60a-dependent chromatin remodeling preserves β-cell function and contributes to the therapeutic benefits of GLP-1R agonists

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Abstract

Impaired glucose-stimulated insulin secretion (GSIS) is a hallmark of β-cell dysfunction in diabetes. Epigenetic mechanisms govern cellular glucose sensing and GSIS by β-cells, but they remain incompletely defined. Here, we found that BAF60a functions as a chromatin regulator that sustains biphasic GSIS and preserves β-cell function under metabolic stress conditions. BAF60a was downregulated in β-cells from obese and diabetic mice, monkeys, and humans. β-cell-specific inactivation of BAF60a in adult mice impaired GSIS, leading to hyperglycemia and glucose intolerance. Conversely, restoring BAF60a expression improved β-cell function and systemic glucose homeostasis. Mechanistically, BAF60a physically interacted with Nkx6.1 to selectively modulate chromatin accessibility and transcriptional activity of target genes critical for GSIS coupling in islet β-cells. A BAF60a V278M mutation associated with decreased β-cell GSIS function was identified in human subjects. Mice carrying this mutation, which disrupted the interaction between BAF60a and Nkx6.1, displayed β-cell dysfunction and impaired glucose homeostasis. In addition, GLP-1R and GIPR expression was significantly reduced in BAF60a-deficient islets, attenuating the insulinotropic effect of GLP-1R agonists. Together, these findings support a role for BAF60a as a component of the epigenetic machinery that shapes the chromatin landscape in β-cells critical for glucose sensing and insulin secretion.

Authors

Xinyuan Qiu, Ruo-Ran Wang, Qing-Qian Wu, Hongxing Fu, Shuaishuai Zhu, Wei Chen, Wen Wang, Haide Chen, Xiuyu Ji, Wenjing Zhang, Dandan Yan, Jing Yan, Li Jin, Rong Zhang, Mengjie Shi, Ping Luo, Yingqing Yang, Qintao Wang, Ziyin Zhang, Wei Ding, Xiaowen Pan, Chengbin Li, Bin Liang, Guoji Guo, Hai-long Piao, Min Zheng, Yan Sheng, Lingyun Zhu, Cheng Hu, Zhuo-Xian Meng

S-acyl transferase ZDHHC13 modulates tumor microenvironment interactions to suppress metastasis in melanoma models

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Abstract

The intratumor microenvironment shapes the metastatic potential of cancer cells and their susceptibility to any immune response. Yet the nature of the signals within the microenvironment that control anti-cancer immunity and how they are regulated is poorly understood. Here, using melanoma as a model, we investigate the involvement in metastatic dissemination and the immune-modulatory microenvironment of Protein S-Acyl Transferases, as an underexplored class of potential therapeutic targets. We find that ZDHHC13, suppresses metastatic dissemination by palmitoylation of CTNND1, leading to stabilization of E-cadherin. Importantly, ZDHHC13 also reshapes the tumor immune microenvironment by suppressing lysophosphatidylcholine (LPC) synthesis in melanoma cells, leading to inhibition of M2-like tumor-associated macrophages that we show degrades E-cadherin via MMP12 expression. Consequently, ZDHHC13 activity suppresses tumor growth and metastasis in immunocompetent mice. Our study highlights the therapeutic potential of targeting the ZDHHC13-E-cadherin axis and its downstream metabolic and immune-modulatory mechanisms, offering additional strategies to inhibit melanoma progression and metastasis.

Authors

Hongjin Li, Jianke Lyu, Yu Sun, Chengqian Yin, Yuewen Li, Weiqiang Chen, Suan-Sin Foo, Xianfang Wu, Colin Goding, Shuyang Chen

Dysfunctional LHX6 pallido-subthalamic projections mediate epileptic events in a mouse model of Leigh Syndrome

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Abstract

Deficits in the mitochondrial energy-generating machinery cause mitochondrial disease (MD), a group of untreatable and usually fatal disorders. Among many severe symptoms, refractory epileptic events are a common neurological presentation of MD. However, the neuronal substrates and circuits for MD-induced epilepsy remain unclear. Here, using mouse models of Leigh Syndrome, a severe form of MD associated to epilepsy, that lack mitochondrial complex I subunit NDUFS4 in a constitutive or conditional manner, we demonstrate that mitochondrial dysfunction leads to a reduction in the number of GABAergic neurons in the rostral external globus pallidus (GPe), and identify a specific affectation of pallidal Lhx6-expressing inhibitory neurons, contributing to altered GPe excitability. Our findings further reveal that viral vector-mediated Ndufs4 re-expression in the GPe effectively prevents seizures and improves the survival in the models. Additionally, we highlight the subthalamic nucleus (STN) as a critical structure in the neural circuit involved in mitochondrial epilepsy, as its inhibition effectively reduces epileptic events. Thus, we have identified a role for pallido-subthalamic projections in the development of epilepsy in the context of mitochondrial dysfunction. Our results suggest STN inhibition as a potential therapeutic intervention for refractory epilepsy in patients with MD providing promising leads in the quest to identify effective treatments.

Authors

Laura Sánchez-Benito, Melania González-Torres, Irene Fernández-González, Laura Cutando, María Royo, Joan Compte, Miquel Vila, Sandra Jurado, Elisenda Sanz, Albert Quintana