Substance P prevents doxorubicin‑induced cardiomyocyte injury by regulating apoptosis and autophagy: In vitro and in vivo evidence

The roles of autophagy and mitophagy in corneal pathology: current knowledge and future perspectives

The cornea is the clear dome that covers the front portion of the globe. The primary functions of the cornea are to promote the refraction of light and to protect the eye from invading pathogens, both of which are essential for the preservation of vision. Homeostasis of each cellular layer of the cornea requires the orchestration of multiple processes, including the ability to respond to stress. One mechanism whereby cells respond to stress is autophagy, or the process of "self-eating." Autophagy functions to clear damaged proteins and organelles. During nutrient deprivation, amino acids released from protein breakdown via autophagy are used as a fuel source. Mitophagy, a selective form of autophagy, functions to clear damaged mitochondria. Thus, autophagy and mitophagy are important intracellular degradative processes that sustain tissue homeostasis. Importantly, the inhibition or excessive activation of these processes result in deleterious effects on the cell. In the eye, impairment or inhibition of these mechanisms have been associated with corneal disease, degenerations, and dystrophies. This review summarizes the current body of knowledge on autophagy and mitophagy at all layers in the cornea in both non-infectious and infectious corneal disease, dystrophies, and degenerations. It further highlights the critical gaps in our understanding of mitochondrial dysfunction, with implications for novel therapeutics in clinical practice.

Cardiovascular protection by DPP-4 inhibitors in preclinical studies: an updated review of molecular mechanisms

Dipeptidyl peptidase 4 (DPP4) inhibitors are a class of antidiabetic medications that cause glucose-dependent increase in incretins in diabetic patients. One of the two incretins, glucagon-like peptide-1 (GLP-1), beside its insulinotropic activity, has been studied for extra pancreatic effects. Most of DPP4 inhibitors (DPP4i) have been investigated in in vivo and in vitro models of diabetic and nondiabetic cardiovascular diseases including heart failure, hypertension, myocardial ischemia or infarction, atherosclerosis, and stroke. Results of preclinical studies proved prominent therapeutic potential of DPP4i in cardiovascular diseases, regardless the presence of diabetes. This review aims to present an updated summary of the cardiovascular protective and therapeutic effects of DPP4 inhibitors through the past 5 years focusing on the molecular mechanisms beneath these effects. Additionally, based on the results summary presented here, future studies may be conducted to elucidate or illustrate some of these findings which can add clinical benefits towards management of diabetic cardiovascular complications.

Integrative Proteomic and Metabolomic Analysis Reveals Metabolic Phenotype in Mice With Cardiac-Specific Deletion of Natriuretic Peptide Receptor A

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are important biological markers and cardiac function regulators. Natriuretic peptide receptor A (NPRA) binds to an ANP or BNP ligand and induces transmembrane signal transduction by elevating the intracellular cyclic guanosine monophosphate (cGMP) levels. However, the metabolic phenotype and related mechanisms induced by NPRA deletion remain ambiguous. Here, we constructed myocardial-specific NPRA deletion mice and detected the heart functional and morphological characteristics by histological analysis and explored the altered metabolic pattern and the expression patterns of proteins by liquid chromatography-mass spectrometry (LC-MS)-based omics technology. NPRA deficiency unexpectedly did not result in significant cardiac remodeling or dysfunction. However, compared with the matched littermates, NPRA-deficient mice had significant metabolic differences. Metabolomic analysis showed that the metabolite levels varied in cardiac tissues and plasma. In total, 33 metabolites were identified in cardiac tissues and 54 were identified in plasma. Compared with control mice, NPRA-deficient mice had 20 upregulated and six downregulated metabolites in cardiac tissues and 25 upregulated and 23 downregulated metabolites in plasma. Together, NPRA deficiency resulted in increased nucleotide biosynthesis and histidine metabolism only in heart tissues and decreased creatine metabolism only in plasma. Further proteomic analysis identified 136 differentially abundant proteins in cardiac tissues, including 54 proteins with higher abundance and 82 proteins with lower abundance. Among them, cytochrome c oxidase subunit 7c and 7b (Cox7c, Cox7b), ATP synthase, H+ transporting, mitochondrial Fo complex subunit F2 (ATP5J2), ubiquinol-cytochrome c reductase, complex III subunit X (Uqcr10), and myosin heavy chain 7 (Myh7) were mainly involved in related metabolic pathways. These results revealed the essential role of NPRA in metabolic profiles and may elucidate new underlying pathophysiological mechanisms of NPRA in cardiovascular diseases.