An integrated single-cell RNA sequencing atlas across mouse models of PKD is constructed, mapping changes in cell type composition, gene expression, and intercellular signaling networks across the whole atlas and within individual models.
Abstract
Polycystic kidney disease (PKD) arises from mutations in cilia-associated genes, such as PKD1 and PKD2, expressed in renal epithelial cells, leading to progressive kidney dysfunction and end-stage kidney disease (ESKD). PKD patients exhibit significant heterogeneity in disease progression, largely due to genetic and environmental modifiers. Like patients, mouse models of PKD also exhibit significant heterogeneity with regards to the gene mutated, age of disease onset, and rate of disease progression. To elucidate the cellular and molecular consequences of these variables, we constructed an integrated single-cell RNA sequencing atlas across mouse models of PKD, mapping changes in cell type composition, gene expression, and intercellular signaling networks across the whole atlas and within individual models. Across models, single cell RNA sequencing (scRNAseq) data revealed increased Spp1 (osteopontin) expression and signaling from PKD-enriched clusters. Global deletion of Spp1 in Pkd1RC/RC mice resulted in a modest reduction in cyst severity and improved kidney function. From these studies, we created a freely available, searchable website (https://bmblx.bmi.osumc.edu/scPKD/) that can be used to identify cross- and intra-model changes in gene expression, guiding researchers to new therapeutic targets for treating PKD.
Underused Drosophila melanogaster offers high genomic and pathway conservation, a wealth of genetic tools, and rapid generation times, making it a reliable and sustainable model for mechanistic, genome-wide, and precision medicine studies.
Jay Deloriea, Cody Casey, Lexee Shearer et al.· Journal of Developmental Bio...· 0 citations
A model in which cyst growth arises from mutually reinforcing signaling, metabolic, and transcriptional programs is synthesized, which support a model in which cyst growth arises from mutually reinforcing signaling, metabolic, and transcriptional programs.
R. Ursu, B. Buchholz, K. Skoczynski· American Journal of Physiolo...· 0 citations
It is demonstrated that TMZ mitigates dystrophic pathology by targeting the ATP6AP2 signaling axis and dampening macrophage-mediated inflammatory responses, highlighting its potential as a novel immunopharmacological therapeutic strategy for DMD.
Lin Zhou, Yu Zhang, Xinxin Tan et al.· International Immunopharmaco...· 0 citations
INTRODUCTION
Identified as a pathological hallmark of all forms of chronic kidney disease (CKD), renal fibrosis contributes to renal failure when dysregulated. In this process, renal fibroblasts act as the primary source of myofibroblasts, which play a pivotal role as the central effector cells.
OBJECTIVES
This study identifies a critical role for the lysine methyltransferase Suv39h1 in regulating fibroblast-myofibroblast transition (FMyT) and renal fibrosis.
METHODS
Fibroblast- and myofibroblast-specific gene knockout in mice was achieved using the Col1a2-CreERT2 and Postn-CreERT2 drivers. The model of renal fibrosis was established by unilateral ureteral obstruction (UUO) or streptozotocin-induced diabetic nephropathy (DN). Transcriptomic alterations were evaluated by RNA-seq.
RESULTS
Our data indicate that the transcriptional upregulation of Su39h1 may be implicated in the process of FMyT, as evidenced by its consistent induction in both employed model systems. Suv39h1 deletion attenuated renal fibrosis in three animal models, consistent with its inhibition of FMyT in fibroblasts. Moreover, the conditional ablation of Suv39h1 within Postn-expressing mature myofibroblasts resulted in a significant abrogation of the pathological remodeling associated with renal fibrosis in mice. Notably, the targeted inhibition of the histone methyltransferase Suv39h1 by chaetocin effectively suppresses fibroblast activation in vitro and ameliorates the pathological progression of renal fibrosis in a murine model. Transcriptomic analysis revealed CXCL10 as a downstream target of Suv39h1. Furthermore, CXCL10 knockdown abolished the protective effect of Suv39h1 insufficiency on renal fibrosis. Mechanistically, CXCL10 regulated FMyT by suppressing the Hippo/YAP pathway.
CONCLUSION
We identify Suv39h1-mediated regulation as a previously unrecognized facet of renal fibrogenesis.
Xiaoyan Wu, Yajun Luo, Caiyi Wu et al.· Journal of Advanced Research· 0 citations
Limb-girdle muscular dystrophy R2/2B (LGMDR2/2B) is an untreatable and progressive late-onset skeletal muscle disease caused by the loss of a membrane-repair protein dysferlin. Even before disease symptom onset, LGMDR2 muscles are infiltrated by pro-inflammatory macrophages (MP), implicating immune cells in disease pathogenesis. While MPs express dysferlin, defining the cell-autonomous roles of dysferlin in MP function has been challenging in vivo due to complex multicellular interactions and altered microenvironment in LGMDR2 muscle.
To address this, we generated human induced pluripotent stem cell (hiPSC)-derived macrophages (iMPs) from three healthy and three LGMDR2 donors to delineate cell-autonomous roles of dysferlin in macrophage: 1) polarization, 2) transcriptional profile, 3) secretome, and 4) phagocytotic and endocytic function.
Despite exhibiting comparable polarization under well-characterized pro- and anti-inflammatory cues, RNAseq analyses revealed downregulation of Gene Ontology terms related to cytokine secretion, phagocytosis, and receptor-mediated endocytosis in LGMDR2 iMPs. Proteomic analysis of iMP conditioned media revealed significant differences in 72 secreted proteins, including numerous chemokines, cytokines, and growth factors, suggesting an altered secretory phenotype. Functional assays found no significant differences in the phagocytosis of E. coli bioparticles or fluorescent myotube debris. However, receptor-mediated endocytosis of AcLDL was significantly lower in both M0 and M2 LGMDR2 vs. healthy iMPs. Pharmacological screens identified clathrin-dependent endocytosis as the primary pathway for AcLDL uptake in both genotypes, with altered clathrin trafficking and reduced scavenger receptor expression likely underlying LGMDR2 endocytic deficits.
Overall, dysferlin loss in iMPs results in cell-autonomously altered transcriptome, secretome, and endocytic function, which may contribute to LGMDR2 muscle pathology and disease progression.
Jain Foundation grant, NIH grant 1R01AR082979-01, National Science Foundation Graduate Research Fellowship
Immune Mechanisms of Human Disease (HUM)
Amber Detwiler, Rachel Luner, Alex Schneider et al.· Journal of Immunology· 0 citations
The premature aging disorder Hutchinson-Gilford Progeria Syndrome (HGPS) is caused by de novo LMNA mutations producing the aberrant Lamin A isoform progerin. HGPS patients die from cardiovascular disease, with their arteries showing extensive cellular and structural remodeling, but the mechanisms driving vascular dysfunction are not fully understood. To define molecular processes underlying progressive vascular degeneration in HGPS, we performed single-cell RNA-sequencing (scRNA-seq) of aortic arch cells from LmnaG609G/G609G mice without atheroprone stimuli. These mice carry the murine equivalent of the most common HGPS-causing mutation and faithfully recapitulate the vascular phenotype. Sequencing was performed at multiple ages to capture disease-related and time-dependent transcriptional changes. We used Smart-seq2 for sequencing, due to its high sensitivity and full-length transcript coverage. Histology, immunostaining and in situ hybridization were used for arterial characterization. The aortic arch of LmnaG609G/G609G mice exhibited a gradual age-dependent vascular smooth muscle cell (VSMC) loss, accompanied by a transient proliferation surge, and ultimately by increased apoptosis. scRNA-seq identified transcriptionally distinct cell populations with unique features that evolved during disease progression. Disease-enriched VSMCs at early stages were characterized by elevated endoplasmic reticulum (ER) stress. With disease development, these VSMCs further underwent phenotypic switching toward a fibroblast-like state, which was predicted to expand through non-cell-autonomous mechanisms. At later stages, disease-enriched VSMCs upregulated apoptotic gene expression, partially coinciding with sustained ER stress. Furthermore, progeria VSMCs showed an increase in both DNA damage and somatic SNVs, with the increased number of SNVs correlating with high expression of ER stress, ROS and p53-related genes. In contrast, progeria-enriched fibroblasts either became activated or increased their cartilage production and showed a delayed accumulation of somatic SNVs compared to VSMCs, highlighting both a cell-type-specific progerin response and differences in somatic mutation susceptibility. Our study shows that progerin leads to somatic mutation accumulation particularly in VSMCs, highlighting the need for early, cell-type-specific therapeutic intervention in HGPS to prevent permanent vascular tissue damage. In addition, the cell-type-specific molecular dynamics of the aortic arch VSMCs and fibroblasts during HGPS disease progression are provided in a user-friendly searchable scRNA-seq database available for preclinical research targeting vascular aging.
Lara G. Merino, Gwladys Revêchon, Santhilal Subhash et al.· Genome Medicine· 1 citation
