Differentiation and Growth-Arrest-Related lncRNA (DAGAR): Initial Characterization in Human Smooth Muscle and Fibroblast Cells.

Vascular smooth muscle cells (SMCs) can transition between a quiescent contractile or "differentiated" phenotype and a "proliferative-dedifferentiated" phenotype in response to environmental cues, similar to what in occurs in the wound healing process observed in fibroblasts. When dysregulated, these processes contribute to the development of various lung and cardiovascular diseases such as Chronic Obstructive Pulmonary Disease (COPD). Long non-coding RNAs (lncRNAs) have emerged as key modulators of SMC differentiation and phenotypic changes. In this study, we examined the expression of lncRNAs in primary human pulmonary artery SMCs (hPASMCs) during cell-to-cell contact-induced SMC differentiation. We discovered a novel lncRNA, which we named Differentiation And Growth Arrest-Related lncRNA (DAGAR) that was significantly upregulated in the quiescent phenotype with respect to proliferative SMCs and in cell-cycle-arrested MRC5 lung fibroblasts. We demonstrated that DAGAR expression is essential for SMC quiescence and its knockdown hinders SMC differentiation. The treatment of quiescent SMCs with the pro-inflammatory cytokine Tumor Necrosis Factor (TNF), a known inducer of SMC dedifferentiation and proliferation, elicited DAGAR downregulation. Consistent with this, we observed diminished DAGAR expression in pulmonary arteries from COPD patients compared to non-smoker controls. Through pulldown experiments followed by mass spectrometry analysis, we identified several proteins that interact with DAGAR that are related to cell differentiation, the cell cycle, cytoskeleton organization, iron metabolism, and the N-6-Methyladenosine (m6A) machinery. In conclusion, our findings highlight DAGAR as a novel lncRNA that plays a crucial role in the regulation of cell proliferation and SMC differentiation. This paper underscores the potential significance of DAGAR in SMC and fibroblast physiology in health and disease.

Trypanosoma cruzi Infection Promotes Vascular Remodeling and Coexpression of α-Smooth Muscle Actin and Macrophage Markers in Cells of the Aorta.

Chagas disease is an emerging global health problem; however, it remains neglected. Increased aortic stiffness (IAS), a predictor of cardiovascular events, has recently been reported in asymptomatic chronic Chagas patients. After vascular injury, smooth muscle cells (SMCs) can undergo alterations associated with phenotypic switch and transdifferentiation, promoting vascular remodeling and IAS. By studying different mouse aortic segments, we tested the hypothesis that Trypanosoma cruzi infection promotes vascular remodeling. Interestingly, the thoracic aorta was the most affected by the infection. Decreased expression of SMC markers and increased expression of proliferative markers were observed in the arteries of acutely infected mice. In acutely and chronically infected mice, we observed cells coexpressing SMC and macrophage (Mo) markers in the media and adventitia layers of the aorta, indicating that T. cruzi might induce cellular processes associated with SMC transdifferentiation into Mo-like cells or vice versa. In the adventitia, the Mo cell functional polarization was associated with an M2-like CD206+arginase-1+ phenotype despite the T. cruzi presence in the tissue. Only Mo-like cells in inflammatory foci were CD206+iNOS+. In addition to the disorganization of elastic fibers, we found thickening of the aortic layers during the acute and chronic phases of the disease. Our findings indicate that T. cruzi infection induces a vascular remodeling with SMC dedifferentiation and increased cell populations coexpressing α-SMA and Mo markers that could be associated with IAS promotion. These data highlight the importance of studying large vessel homeostasis in Chagas disease.

Exploring the Toxicity, Lung Distribution, and Cellular Uptake of Rifampicin and Ascorbic Acid-Loaded Alginate Nanoparticles as Therapeutic Treatment of Lung Intracellular Infections.

Nanotechnology is a very promising technological tool to combat health problems associated with the loss of effectiveness of currently used antibiotics. Previously, we developed a formulation consisting of a chitosan and tween 80-decorated alginate nanocarrier that encapsulates rifampicin and the antioxidant ascorbic acid (RIF/ASC), intended for the treatment of respiratory intracellular infections. Here, we investigated the effects of RIF/ASC-loaded NPs on the respiratory mucus and the pulmonary surfactant. In addition, we evaluated their cytotoxicity for lung cells in vitro, and their biodistribution on rat lungs in vivo after their intratracheal administration. Findings herein demonstrated that RIF/ASC-loaded NPs display a favorable lung biocompatibility profile and a uniform distribution throughout lung lobules. RIF/ASC-loaded NPs were mainly uptaken by lung macrophages, their primary target. In summary, findings show that our novel designed RIF/ASC NPs could be a suitable system for antibiotic lung administration with promising perspectives for the treatment of pulmonary intracellular infections.