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Biology subjects

Goldenberg, N. M.

Publications and source records attributed to Goldenberg, N. M..

4 recordsLinked to original sources

Cardiomyocyte NLRP3 signaling in right heart failure is sexually dimorphic via estrogen receptor α

RationaleRV adaptation in pulmonary hypertension is sexually dimorphic and more preserved in women. NLRP3 inflammasome activation contributes to RV failure (RVF) development. However, regulators and downstream effects of NLRP3 activation in the RV remain unknown. ObjectivesWe investigated whether NLRP3 inflammasome activation in RVF is sexually dimorphic, whether NLRP3 is active in RV cardiomyocytes (RVCMs) and causes RVCM contractile dysfunction, and whether 17{beta}-estradiol (E2) and its receptor ER attenuate this process. MethodsWe studied RV tissues from PAH patients with RVF, RV tissues and RVCMs isolated from wild-type and ER loss-of-function mutant rats with RVF, isolated perfused rat hearts, and human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes. NLRP3 activation was assessed via RNA-sequencing, proteomics, immunostaining, and downstream target quantification. RV contractility was assessed via pressure-volume loops, perfused heart studies, and contractility and calcium assessments in isolated RVCMs. Measurements and Main ResultsNLRP3 was upregulated in RVCMs during RVF and resulted in altered RVCM calcium handling and RVCM contractile dysfunction. In human RVs, hiPSC-cardiomyocytes and rat RVs, NLRP3 activation and NLRP3-induced RVCM contractile dysfunction were sexually dimorphic and male-biased. Ovariectomy and loss of ER in females eliminated this sex bias. E2, via ER, prevented RVCM NLRP3 activation and NLRP3-induced RVCM contractile dysfunction in males and ovariectomized females during both acute and chronic RV pressure overload. ER directly interacted with NLRP3. ConclusionsNLRP3-driven RVCM contractile dysfunction is male-biased. E2 inhibits NLRP3 through ER to preserve RVCM contractility. Targeting E2-ER-NLRP3 signaling may offer novel therapeutic strategies for RVF in low estrogen states. ImpactThis is the first study to define a novel estradiol-estrogen receptor -NLRP3 axis that modulates RV cardiomyocyte function and RV adaptation in pulmonary hypertension. We demonstrate for the first time that NLRP3 activation is therapeutically targetable in low estrogen states via NLRP3 inhibitors or 17{beta}-estradiol. These findings have direct implications for therapeutic strategies aimed at preserving or restoring RV contractile function in pulmonary hypertension, a current area of unmet clinical need.

molecular biology↗

NINJ1 mediates hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (IRI) results from interrupted perfusion to the liver and contributes to acute liver dysfunction such as following liver transplantation. Lytic cell death pathways are major drivers of IRI and the subsequent inflammatory response. The transmembrane protein ninjurin-1 (NINJ1) was identified as the key executor of terminal plasma membrane rupture across multiple lytic cell death pathways implicated in hepatic IRI. We hypothesized that NINJ1-mediated lytic cell death drives IRI and that its therapeutic inhibition would mitigate liver IRI. Using human liver specimens, we found that NINJ1 is highly expressed in human liver tissue and that its activation correlates with early allograft dysfunction in patients undergoing liver transplantation. Utilizing a segmental hepatic IRI model in mice and rats, Ninj1 genetic deletion or pharmacologic inhibition diminished acute liver injury. Mice with hepatocyte- or macrophage-specific Ninj1 knockout both had reduced hepatocellular injury following IRI, suggesting that NINJ1 within both populations contributes to the resulting liver injury. Mechanistically, we found that hepatocytes and Kupffer cells are highly susceptible to hypoxia-induced NINJ1-mediated plasma membrane rupture, which can be pharmacologically prevented. These data position NINJ1 as a potential new therapeutic target to limit hepatic IRI, with important implications for organ preservation during liver transplantation.

immunology↗

NINJ1 is activated by calcium-driven plasma membrane lipid scrambling during lytic cell death

NINJ1 is the terminal executioner of cellular rupture in multiple lytic cell death pathways through its clustering in the plasma membrane. Its activation trigger, however, remains unknown. We found that NINJ1-mediated plasma membrane rupture depends on calcium influx into the cell, which suffices to induce NINJ1-mediated rupture. Using genetic and pharmacologic approaches in macrophages, we show calcium drives membrane rupture through phospholipid scrambling by the calcium-activated scramblase TMEM16F. We next tested whether this calcium-activated NINJ1 mechanism is the elusive pathway by which extracellular ATP stimulates cellular rupture. We show that ATP-stimulation of P2X7R induces NINJ1-mediated cell lysis via calcium influx and TMEM16F lipid scrambling, independently of inflammasomes, pannexins and gasdermin D. Our work reveals the mechanism of NINJ1 activation and solves the long-standing mystery of ATP-induced cytolysis. SummaryElevated cytosolic calcium drives NINJ1-mediated cellular rupture during lytic cell death through plasma membrane lipid scrambling.

cell biology↗

Glycine targets NINJ1-mediated plasma membrane rupture to provide cytoprotection

First recognized 35 years ago, glycine is known to protect cells against plasma membrane rupture from diverse types of tissue injury. This robust and widely observed effect has been speculated to target a late downstream process common to multiple modes of tissue injury. The molecular target of glycine cytoprotection, however, remains entirely elusive. We hypothesized that glycine targets ninjurin-1 (NINJ1), a newly identified executioner of plasma membrane rupture in pyroptosis, necrosis, and post-apoptotic cell death. NINJ1 is thought to cluster within the plasma membrane to cause cell rupture. Here, we first demonstrate that NINJ1 knockout functionally and morphologically phenocopies glycine cytoprotection in mouse and human macrophages stimulated to undergo lytic cell death. Next, we show that glycine treatment prevents NINJ1 clustering thereby preserving cellular integrity. By identifying NINJ1 as a glycine target, our data help resolve a long-standing mechanism of glycine cytoprotection. This new understanding will inform the development of cell preservation strategies to counter pathologic lytic cell death pathways. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=147 SRC="FIGDIR/small/471765v2_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@b9c3d9org.highwire.dtl.DTLVardef@1e903f0org.highwire.dtl.DTLVardef@1018498org.highwire.dtl.DTLVardef@a819b9_HPS_FORMAT_FIGEXP M_FIG C_FIG SummaryGlycine is known to protect cells against plasma membrane rupture from diverse types of tissue injury by an unknown mechanism. The authors demonstrate that NINJ1, a newly identified executioner of plasma membrane rupture across lytic cell death pathways, is a glycine target and resolve a longstanding mechanism of glycine cytoprotection.

cell biology↗