Biology subjects

Emtiazjoo, A.

Publications and source records attributed to Emtiazjoo, A..

3 recordsLinked to original sources

bioRxiv2025

Exogenous BMP9 therapy ameliorates primary graft dysfunction post lung transplantation

Primary graft dysfunction (PGD) is a leading cause of early mortality after lung transplantation and is driven by ischemia-reperfusion injury (IRI), which destabilizes the pulmonary endothelium. Bone morphogenetic protein 9 (BMP9), a vascular quiescence factor of the TGF superfamily, maintains endothelial homeostasis through ALK-1/BMPR2-mediated signaling. Herein, this work identified a previously unrecognized suppression of BMP9 signaling during early reperfusion in a murine orthotopic lung transplant model. Allograft transcriptomic profiling revealed rapid downregulation of BMP9 pathway components, including Bmpr2, Acvrl1, Smad5, and Eng. Recombinant BMP9 administered at reperfusion enhanced Id1 expression in pulmonary endothelium, reduced neutrophil infiltration, preserved vascular barrier function, and improved oxygenation. In vitro, BMP9 attenuated proinflammatory cytokine release following simulated cold ischemia-reperfusion injury in human lung endothelial cells. Plasma from lung transplant recipients, regardless of PGD status, had impaired BMP9-induced ID1 expression in endothelial cells, with the most profound suppression observed in patients with interstitial lung disease. These findings implicate transient loss of BMP9 signaling as a key feature of transplant-induced vascular injury and support the therapeutic potential of BMP9 supplementation to restore endothelial homeostasis and improve early graft outcomes.

immunology↗

bioRxiv2024

Predicting Primary Graft Dysfunction in Lung Transplantation: Machine Learning-Guided Biomarker Discovery

BACKGROUNDThere is an urgent need to better understand the pathophysiology of primary graft dysfunction (PGD) so that point-of-care methods can be developed to predict those at risk. Here we utilize a multiplex multivariable approach to define cytokine, chemokines, and growth factors in patient-matched biospecimens from multiple biological sites to identify factors predictive of PGD. METHODSBiospecimens were collected from patients undergoing bilateral LTx from three distinct sites: donor lung perfusate, post-transplant bronchoalveolar lavage (BAL) fluid (2h), and plasma (2h and 24h). A 71-multiplex panel was performed on each biospecimen. Cross-validated logistic regression (LR) and random forest (RF) machine learning models were used to determine whether analytes in each site or from combination of sites, with or without clinical data, could discriminate between PGD grade 0 (n = 9) and 3 (n = 8). RESULTSUsing optimal AUROC, BAL fluid at 2h was the most predictive of PGD (LR, 0.825; RF, 0.919), followed by multi-timepoint plasma (LR, 0.841; RF, 0.653), then perfusate (LR, 0.565; RF, 0.448). Combined clinical, BAL, and plasma data yielded strongest performance (LR, 1.000; RF, 1.000). Using a LASSO of the predictors obtained using LR, we selected IL-1RA, BCA-1, and Fractalkine, as most predictive of severe PGD. CONCLUSIONSBAL samples collected 2h post-transplant were the strongest predictors of severe PGD. Our machine learning approach not only identified novel cytokines not previously associated with PGD, but identified analytes that could be used as a point-of-care cytokine panel aimed at identifying those at risk for developing severe PGD.

immunology↗

bioRxiv2024

MerTK-dependent efferocytosis by monocytic-MDSCs mediates resolution of post-lung transplant injury

ABSTRACTO_ST_ABSRationaleC_ST_ABSPatients with end stage lung diseases require lung transplantation (LTx) that can be impeded by ischemia-reperfusion injury (IRI) leading to subsequent chronic lung allograft dysfunction (CLAD) and inadequate outcomes. ObjectivesWe examined the undefined role of MerTK (receptor Mer tyrosine kinase) on monocytic myeloid-derived suppressor cells (M-MDSCs) in efferocytosis (phagocytosis of apoptotic cells) to facilitate resolution of lung IRI. MethodsSingle-cell RNA sequencing of lung tissue and BAL from post-LTx patients was analyzed. Murine lung hilar ligation and allogeneic orthotopic LTx models of IRI were used with Balb/c (WT), cebpb-/- (MDSC-deficient), Mertk-/- or MerTK-CR (cleavage resistant) mice. Lung function, IRI (inflammatory cytokine and myeloperoxidase expression, immunohistology for neutrophil infiltration), and flow cytometry of lung tissue for efferocytosis of apoptotic neutrophils were assessed in mice. Measurements and Main ResultsA significant downregulation in MerTK-related efferocytosis genes in M-MDSC populations of CLAD patients compared to healthy subjects was observed. In the murine IRI model, significant increase in M-MDSCs, MerTK expression and efferocytosis was observed in WT mice during resolution phase that was absent in cebpb-/- Land Mertk-/- mice. Adoptive transfer of M-MDSCs in cebpb-/- mice significantly attenuated lung dysfunction, and inflammation leading to resolution of IRI. Additionally, in a preclinical murine orthotopic LTx model, increases in M-MDSCs were associated with resolution of lung IRI in the transplant recipients. In vitro studies demonstrated the ability of M-MDSCs to efferocytose apoptotic neutrophils in a MerTK-dependent manner. ConclusionsOur results suggest that MerTK-dependent efferocytosis by M-MDSCs can significantly contribute to the resolution of post-LTx IRI.

immunology↗