Citations

Age-related gastrointestinal dysfunction is common, but the mechanisms of aging-associated smooth muscle failure remain unclear. We show that aging in mice slows whole gut and colonic transit, increases regional stiffness, and reduces smooth muscle contractility. Inducible smooth muscle cell (SMC)– specific deletion of Piezo1 preserved youthful transit and force generation, whereas Piezo1 activation in young mice phenocopied aging-associated transit delay. Single-cell transcriptomics, RNA velocity, stiffness-controlled cell and tissue cultures, and pharmacologic studies revealed that Piezo1 couples increased stiffness to Ca 2+ –calcineurin–NFAT signaling, loss of contractile gene programs, leading to age- related contractile loss and contractile-to-synthetic SMC remodeling and gut wall stiffening. Human intestinal SMCs supported conservation of this pathway, and PIEZO1 gain-of-function carriers showed a trend toward delayed colonic transit. Thus, maladaptive SMC Piezo1 mechanotransduction is a targetable mechanism of aging-associated gut dysmotility. Aging alters organ structure, yet how these changes drive functional decline remains poorly defined. We show that progressive stiffening of the gut with age activates the mechanosensitive ion channel Piezo1 in smooth muscle cells, initiating a maladaptive response that impairs contractility and slows intestinal transit. On the other hand, deletion of smooth muscle Piezo1 prevents age-related gut dysmotility. These findings reveal that age-related physical shifts actively drive functional decline through mechanotransduction pathways. By identifying Piezo1 as a critical link between tissue mechanics and organ aging, this work provides a framework for understanding how mechanical cues contribute to age-related dysfunction in the gut and possibly other smooth muscle organs.

ABSTRACT The enteric nervous system (ENS) is a complex peripheral neural network that coordinates gastrointestinal motility through highly organized synaptic communication. Although tissue-resident muscularis macrophages (MMs) closely associate with enteric neurons, whether they regulate enteric synaptic organization remains unknown. In the central nervous system (CNS), microglia sculpt neural circuits through complement-dependent synaptic remodeling, raising the possibility that analogous neuroimmune mechanisms operate in the gut. Here, we identify a previously unrecognized role for C1qa□ MMs in regulating enteric synaptic homeostasis and gastrointestinal motility. Using macrophage-specific constitutive and inducible C1qa deletion models, single-cell RNA sequencing, enteric synaptosome proteomics, physiology, and advanced imaging, we demonstrate that loss of MMs-derived C1qa increases enteric synaptic density without altering neuronal numbers. C1qa deficiency induced broad transcriptional changes in enteric neurons and macrophages, including altered synapse-associated, lysosomal, and endocytic programs. Proteomic analysis revealed that enteric synapses share a conserved molecular architecture with brain synapses while exhibiting distinct gastrointestinal-specific complement-associated synaptic networks enriched for structural and receptor-localization pathways. Functionally, macrophage-specific C1qa deletion altered excitatory and inhibitory enteric neurotransmission, enhanced cholinergic signaling, reduced nitrergic responses, and accelerated gastrointestinal transit, while smooth muscle responsiveness remained preserved. C1qa□ MMs displayed transcriptional and functional features consistent with a phagocytic synapse-remodeling phenotype, including enrichment of complement, lysosomal, and engulfment pathways. Loss of C1qa impaired macrophage phagocytic activity both in vitro and in vivo and was associated with synapse accumulation and altered macrophage morphology. Importantly, inducible deletion of C1qa in adulthood recapitulated the synaptic and motility phenotypes, demonstrating that C1qa□ MMs continuously regulate enteric synaptic organization beyond development. Together, these findings identify a complement-dependent neuroimmune mechanism that regulates enteric circuit organization and gut motility, establishing MMs as active modulators of adult ENS synaptic homeostasis. Abstract Figure

Circulating extracellular vesicles, proinflammatory/pro-oxidant metabolites, and history of preeclampsia may be used as biomarkers for diagnosis of early CAC in postmenopausal women.

Background: Preeclampsia (PE) is a severe hypertensive disorder of pregnancy of unknown pathophysiology. We previously have reported the presence of senescence in kidney and fat tissue of PE women, as well as accelerated epigenetic aging, which prompted us to postulate that cellular senescence may drive development of PE. Methods: We prospectively collected sera from pregnant women throughout pregnancy, and using multiplex Luminex analysis, measured 50 markers of the senescence-associated secretory phenotype (SASP). Comparisons were made between women who developed PE (n=10) vs. normotensive pregnancies (n=10). We then injected human PE serum into the IL-10KO mouse to induce PE and assess whether PE is associated with development of senescence. We measured plasma p16, a circulating indicator of cellular senescence, before and after inducing PE. We also compared plasma p16 and expressions of senescence-associated genes in the hearts and aortas of regular pregnant (PG, no PE serum injection) and PE mice (n=4). Results: There was a significant increase in several SASP markers in sera of women who developed PE, beginning in the first trimester, through delivery. Notably, eotaxin, MCP1, GROb, MIF, MMP2, TNFRII, IGFBP2 were significantly increased in PE women compared to their normotensive peers throughout all trimesters. Mice injected with PE serum exhibited all features of PE, as reported earlier. When measuring plasma p16 before and after PE serum injection, animals had higher values upon inducing PE. Plasma samples of PE mice demonstrated higher p16 concentrations compared to the PG group. The aortas of PE mice exhibited increased expressions of senescence associated genes p16, il6, and mcp1, whereas in the hearts, p16, Il1a and il8 were upregulated. Conclusion: The SASP is present very early in human pregnancy, even before PE has developed. Injection of SASP-enriched PE serum into IL-10KO mice induces cellular senescence in different tissues resulting in a PE phenotype. These results suggest that senescence may be an underlying mechanism of PE.