Carbon monoxide-induced autophagy enhances human mesenchymal stromal cell function via paracrine actions in murine polymicrobial sepsis.

Sepsis is a life-threatening process due to organ dysfunction resulting from severe infections. Mesenchymal stromal cells (MSCs) are being investigated as therapy for sepsis, along with conditioning regimens to improve their function. Carbon monoxide (CO) gas, which is cytoprotective at low doses, induces autophagy and is a mediator of inflammation. We evaluated CO-induced autophagy in human MSCs (hMSCs), and its impact on cell function in murine cecal ligation and puncture. Conditioning of hMSCs with CO ex vivo resulted in enhanced survival and bacterial clearance in vivo, and neutrophil phagocytosis of bacteria in vitro. Decreased neutrophil infiltration and less parenchymal cell death in organs were associated with increased macrophage efferocytosis of apoptotic neutrophils, promoting resolution of inflammation. These CO effects were lost when the cells were exposed to autophagy inhibition prior to gas exposure. When assessing paracrine actions of CO-induced autophagy, extracellular vesicles (EVs) were predominantly responsible. CO had no effect on EV production, but altered their miRNA cargo. Increased expression of miR-145-3p and miR-193a-3p by CO was blunted with disruption of autophagy, and inhibitors of these miRNAs led to a loss of neutrophil phagocytosis and macrophage efferocytosis. Collectively, CO-induced autophagy enhanced hMSC function during sepsis via paracrine actions of MSC-derived EVs.

Lymphangioleiomyomatosis: circulating levels of FGF23 and pulmonary diffusion / Linfangioleiomiomatose: níveis circulantes de FGF23 e difusão pulmonar

ABSTRACT Objective: Lymphangioleiomyomatosis (LAM) is a rare, destructive disease of the lungs with a limited number of determinants of disease activity, which are a critical need for clinical trials. FGF23 has been implicated in several chronic pulmonary diseases. We aimed to determine the association between serum FGF23 levels and pulmonary function in a cohort of patients with LAM. Methods: This was a descriptive single-center study in which subjects with LAM and controls with unreported lung disease were recruited. Serum FGF23 levels were measured in all subjects. Clinical data, including pulmonary function testing, were retrospectively obtained from electronic medical records of LAM subjects. Associations between FGF23 levels and clinical features of LAM were explored via nonparametric hypothesis testing. Results: The sample comprised 37 subjects with LAM and 16 controls. FGF23 levels were higher in the LAM group than in the control group. In the LAM group, FGF23 levels above the optimal cutoff point distinguished 33% of the subjects who had nondiagnostic VEGF-D levels. Lower FGF23 levels were associated with impaired DLCO (p = 0.04), particularly for those with isolated diffusion impairment with no other spirometric abnormalities (p = 0.04). Conclusions: Our results suggest that FGF23 is associated with pulmonary diffusion abnormalities in LAM patients and elicit novel mechanisms of LAM pathogenesis. FGF23 alone or in combination with other molecules needs to be validated as a biomarker of LAM activity in future clinical research.

RESUMO Objetivo: A linfangioleiomiomatose (LAM) é uma doença rara e destrutiva dos pulmões com um número limitado de determinantes da atividade da doença, que são uma necessidade crítica para ensaios clínicos. O FGF23 já foi implicado em várias doenças pulmonares crônicas. O nosso objetivo foi determinar a associação entre os níveis séricos de FGF23 e a função pulmonar em uma coorte de pacientes com LAM. Métodos: Estudo descritivo unicêntrico no qual foram recrutados indivíduos com LAM e controles com doenças pulmonares não declaradas. Os níveis séricos de FGF23 foram medidos em todos os indivíduos. Os dados clínicos, incluindo testes de função pulmonar, foram obtidos retrospectivamente a partir dos prontuários eletrônicos dos indivíduos com LAM. As associações entre os níveis de FGF23 e as características clínicas da LAM foram exploradas por meio do teste de hipóteses não paramétrico. Resultados: A amostra incluiu 37 indivíduos com LAM e 16 controles. Os níveis de FGF23 foram mais altos no grupo LAM do que no grupo controle. No grupo LAM, níveis de FGF23 acima do ponto de corte ideal distinguiram 33% dos indivíduos com níveis não diagnósticos de VEGF-D. Níveis mais baixos de FGF23 estavam associados à DLCO comprometida (p = 0,04), particularmente naqueles com comprometimento isolado da difusão e sem outras alterações espirométricas (p = 0,04). Conclusões: Nossos resultados sugerem que o FGF23 está associado a alterações na difusão pulmonar em pacientes com LAM e potencialmente indicam novos mecanismos de patogênese da LAM. O FGF23 isoladamente ou em combinação com outras moléculas precisa ser validado como um biomarcador da atividade da LAM em futuras pesquisas clínicas.