Biology subjects

Cibi, D. M.

Publications and source records attributed to Cibi, D. M..

3 recordsLinked to original sources

bioRxiv2023

Inhibition of an immunometabolic axis of mTORC1 activation extends mammalian healthspan

Human ageing is associated with metabolic dysfunction, sarcopenia and frailty that taken together reduce healthspan. For age-associated diseases and lifespan, ERK, AMPK and mTORC1 represent critical pathways, across species1-7. Here we examined the hypothesis that IL11, recently shown to regulate ERK/mTORC1, is an inflammaging factor important for healthspan. As mice age, IL11 is progressively upregulated in liver, skeletal muscle, and fat to stimulate an ERK/AMPK/mTORC1 axis of cellular, tissue- and organismal-level ageing pathologies. In old mice, deletion of Il11 or Il11ra1 protects against metabolic multi-morbidity, sarcopenia, and frailty. Administration of anti-IL11 therapy to elderly mice for six months reactivates an age-repressed program of white fat beiging, reverses metabolic dysfunction, restores muscle function, and reduces frailty. Across studies, inhibition of IL11 lowers epigenetic age, reduces telomere attrition, and preserves mitochondrial function. Towards clinical translation, we generated, humanised, and engineered a neutralising, high-affinity IL11 antibody. These studies identify IL11 as a key inflammaging factor and therapeutic target for mammalian healthspan.

molecular biology↗

bioRxiv2023

YAP/TAZ are Crucial Regulator of Macrophage-mediated Pulmonary Inflammation and Fibrosis after Bleomycin-induced Injury

Pulmonary fibrosis (PF) is the most common form of end stage interstitial devastating lung disease characterized by the scarring of lung due to excessive production of extracellular matrix (ECM). Recent studies have revealed the impact of macrophages in inflammation-induced fibrosis and distinct subsets of macrophages differentially contributes to the development of PF. However, the regulatory mechanisms and proinflammatory/profibrotc behaviour of heterogeneous population of lung macrophages during fibrogenesis remain incompletely understood. Here, we demonstrate the macrophage-specific role of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) in the development of bleomycin-induced inflammation and PF in mice. Both YAP/TAZ are activated in lung macrophages of fibrotic patients and of mice after bleomycin-induced injury. Myeloid-specific genetic deletion of Yap/Taz resulted in reduced recruitment of monocyte-derived alveolar macrophages (Mo-AMs), leading to an impaired inflammatory response, reduced PF and improved regeneration of alveolar epithelial cells in bleomycin-injured lung. However, overexpression of Yap in macrophages augmented the Mo-AMs recruitment in lung leading to increased proinflammatory response, exacerbated fibrotic response and decreased regeneration of alveolar epithelial cells in bleomycin-injured lung. We demonstrate that YAP/TAZ regulate PF through the activation of macrophage recruitment driver C-C motif chemokine ligand 2 (CCL2) and blocking of CCL2 with neutralizing antibody prevented YAP-induced inflammatory and fibrotic response. We also demonstrate that YAP/TAZ regulate macrophage polarization as well as macrophage-fibroblasts crosstalk by regulating expression of Methyl-CpG-binding domain 2 (MBD2) during bleomycin-induced PF. Taken together, we show that YAP/TAZ are potent regulators of macrophage polarization, infiltration and macrophage-mediated proinflammatory/profibrotic response during PF.

molecular biology↗

bioRxiv2022

Semaphorin3F reduces vascular endothelial and smooth muscle cell PI3K activation and decreases neointimal plaque formation

We previously conducted genetic analyses, and identified semaphorin signaling as associating with coronary artery disease. Of the semaphorins, human vascular expression profiling suggested SEMA3F as potentially linked to atherogenesis. In hyperlipidemic mice, SEMA3F reduced aortic lesion area, and increased fibrous cap endothelial content, leading to plaque stability. In a disturbed-flow-mediated endothelial dysfunction-driven lesion model, the absence of Sema3f increased plaques, further implicating SEMA3F in endothelial function. Monocyte adhesion to Sema3f-/- vascular endothelial cells (VECs) was elevated, driven by increased PI3K activity, leading to increased NF-{kappa}B-mediated elevation in VCAM1 and ICAM1 expression, suggesting that SEMA3F reduces VEC PI3K activity. Increased permeability led to increased monocyte transmigration through Sema3f-/- VECs, and mTOR phosphorylation was decreased, suppressing VE-cadherin expression and cell-cell adherens junction stability. Actomyosin fiber formation was decreased in Sema3f-/- VECs, which was reversed by PI3K inhibition, further implicating SEMA3F in adherens junction stability. In Sema3f-/- vascular smooth muscle cells (VSMCs), active PI3K was also increased. PI3K facilitates VSMC proliferation, migration, and pro-atherogenic phenotype switching, which were reduced by SEMA3F. In agreement, in a model of VSMC proliferation and migration-induced neointima formation, SEMA3F reduced plaques. Semaphorin3F is causally atheroprotective. SEMA3Fs suppression of VEC and VSMC PI3K activation may contribute to its atheroprotection.

physiology↗