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Zhu, J.-y.

Publications and source records attributed to Zhu, J.-y..

3 recordsLinked to original sources

Senescence and DNA Damage-Induced Inflammation Drive Heart Failure with Preserved Ejection Fraction in Cardiovascular Kidney Metabolic Syndrome

IntroductionHeart failure with preserved ejection fraction (HFpEF) is strongly associated with cardiometabolic comorbidities, including obesity, diabetes, hypertension, chronic kidney disease and aging, yet the mechanistic contribution of cellular senescence to HFpEF pathogenesis remains poorly defined. Methods and ResultsTo model clinically relevant HFpEF, we subjected p16-3MR mice to a novel chronic "four-hit" cardiovascular-kidney-metabolic stress regimen (10 months of a high-fat diet, low-dose streptozotocin, L-NAME, and aging). These mice developed a robust HFpEF phenotype characterized by left ventricular hypertrophy, impaired diastolic function (reduced E'/A' and elevated E/E'), preserved ejection fraction, reduced -dP/dt, exercise intolerance, pulmonary congestion, and increased cardiac CD68 macrophage infiltration. Cardiac proteomics identified 821 proteins significantly altered by four-hit stress. Selective genetic ablation of p16 senescent cells using ganciclovir ameliorated HFpEF phenotypes, reduced cardiac p16 expression and inflammation, and normalized proteomic remodeling, without affecting body weight or glycemic status. Comparative network analysis of mouse and human HFpEF cardiac proteomes revealed highly concordant upstream regulatory networks, prominently involving cell-cycle control, DNA damage responses, and inflammatory signaling. Immunohistochemical analysis of human HFpEF cardiac biopsies confirmed increased p16, {gamma}H2AX, STING, IRF3, NF-{kappa}B p65, and CD68 macrophages, mirroring the murine findings. The 4-Hit mice also developed chronic diabetic kidney disease with increased kidney inflammation, both of which were attenuated by Senolytic therapy. Mechanistically, the cGAS-STING (cyclic GMP-AMP synthase - stimulator of interferon genes) is activated in response to damaged DNA, which in turn activates the downstream immune responses, including NF-{kappa}B and interferons. Cross-species validation further demonstrated that combined metabolic stress impaired cardiac function and nephrocyte function in Drosophila. Cardiac and nephrocyte dysfunctions were independently rescued by cardiomyocyte-specific and nephrocyte-specific inhibition of the cGAS-STING pathway, respectively. In human iPSC-derived cardiomyocytes, irradiation and palmitate induced senescence, DNA damage sensing via ZBP1, and activation of the cGAS-STING-IRF3 signaling axis; ZBP1 knockdown or senolytic treatment suppressed this inflammatory axis. ConclusionsAcross mouse, human, fly, and human iPSC models, our findings identify DNA damage-driven senescence and ZBP1-cGAS-STING signaling as conserved, causal mechanisms linking cardiovascular-kidney-metabolic comorbidities to HFpEF, highlighting senescence and innate immune pathways as promising therapeutic targets.

pathology↗

HIV-1 Nef acts in synergy with APOL1-G1 to induce nephrocyte cell death in a new Drosophila model of HIV-related kidney diseases

BackgroundPeople carrying two APOL1 risk alleles (RA) G1 or G2 are at greater risk of developing HIV-associated nephropathy (HIVAN). Studies in transgenic mice showed that the expression of HIV-1 genes in podocytes, and nef in particular, led to HIVAN. However, it remains unclear whether APOL1-RA and HIV-1 Nef interact to induce podocyte cell death. MethodWe generated transgenic (Tg) flies that express APOL1-G1 (derived from a child with HIVAN) and HIV-1 nef specifically in the nephrocytes, the fly equivalent of mammalian podocytes, and assessed their individual and combined effects on the nephrocyte filtration structure and function. ResultsWe found that HIV-1 Nef acts in synergy with APOL1-G1 resulting in nephrocyte structural and functional defects. Specifically, HIV-1 Nef itself can induce endoplasmic reticulum (ER) stress without affecting autophagy. Furthermore, Nef exacerbates the organelle acidification defects and autophagy reduction induced by APOL1-G1. The synergy between HIV-1 Nef and APOL1-G1 is built on their joint effects on elevating ER stress, triggering nephrocyte dysfunction and ultimately cell death. ConclusionsUsing a new Drosophila model of HIV-1-related kidney diseases, we identified ER stress as the converging point for the synergy between HIV-1 Nef and APOL1-G1 in inducing nephrocyte cell death. Given the high relevance between Drosophila nephrocytes and human podocytes, this finding suggests ER stress as a new therapeutic target for HIV-1 and APOL1-associated nephropathies. HIGHLIGHTSO_LIA new transgenic Drosophila model to study the pathogenesis of HIV-1-related kidney diseases with nephrocyte-specific expression of HIV-1 nef and an APOL1-G1 risk allele derived from a patient with HIVAN. C_LIO_LIAPOL1-G1 caused organelle acidification defects, reduced formation of autophagolysosomes, and reduced autophagy and protein aggregation, which culminated in ER stress. C_LIO_LIHIV-1 Nef induced ER stress through an autophagy-independent pathway. Furthermore, Nef and APOL1-G1 acted synergistically to heighten ER stress, which resulted in nephrocyte dysfunction and cell death. C_LI SIGNIFICANCE STATEMENTAPOL1 risk alleles are strongly linked to HIV-associated nephropathy (HIVAN) in people of African descent, but how HIV-1 and APOL1 interact and which pathways they might converge upon is unclear. A new Drosophila model to study HIV-1 Nef and APOL1-G1 (a risk allele) showed that Nef can induce ER stress in nephrocytes by itself, as well as exacerbate the organelle acidification defects and reduced autophagy induced by APOL1-G1, which further stimulates ER stress to a level that could cause nephrocyte cell death. Thus, we identified ER stress as the converging point for the synergy between APOL1-G1 and HIV-1 Nef in kidney cells, providing a potential therapeutic target for HIV-1 and APOL1-associated nephropathies.

molecular biology↗

Autophagy inhibition rescues structural and functional defects caused by the loss of mitochondrial chaperone Hsc70-5/mortalin in Drosophila

We investigate in larval and adult Drosophila models whether loss of the mitochondrial chaperone Hsc70-5/mortalin is sufficient to cause pathological alterations commonly observed in Parkinson disease. At affected larval neuromuscular junctions, no effects on terminal size, bouton size or number, synapse size, or number were observed, suggesting that we study an early stage of pathogenesis. At this stage, we noted a loss of synaptic vesicle proteins and active zone components, delayed synapse maturation, reduced evoked and spontaneous excitatory junctional potentials, increased synaptic fatigue, and cytoskeleton rearrangements. The adult model displays ATP depletion, altered body posture, and susceptibility to heat-induced paralysis. Adult phenotypes could be suppressed by knockdown of DJ-1b, LRRK, p50, p150, Atg1, Atg101, Atg5, Atg7, and Atg12. The knockdown of components of the autophagy machinery or overexpression of human mortalin broadly rescued larval and adult phenotypes, while disease-associated HSPA9 variants did not. Overexpression of Pink1 or promotion of autophagy exacerbated defects.

genetics↗