Duner, P. | bioRxiv Science

bioRxiv2025

Shedding of mitochondrial Voltage-Dependent Anion Channel-1 (VDAC1) Reflects COVID-19 Severity and Reveals Macrophage Dysfunction

COVID-19 severity correlates with lymphopenia and increased pro-inflammatory cytokines. However, the dysfunction of tissue macrophages in COVID-19 patients during the inflammatory cytokine storm has not been fully elucidated. Hospitalized COVID-19 patients were divided into three groups based on their symptomatic severity: exhibiting mild, moderate, or severe symptoms. Patients exhibited successively increased serum levels of mitochondrial voltage-dependent anion channel 1 (VDAC1) at days 0, 3, 7, 10, and 14, returning to those of non-infected subjects at day 28. Serum level of VDAC1 was positively correlated with COVID-19 severity and with increased white blood cell (WBC), neutrophil, lymphocyte, procalcitonin (PCT), and gamma-glutamyltransferase (GT) levels. Peripheral blood mononuclear cells (PBMCs) from hospitalized COVID-19 patients showed increased VDAC1 content concomitant with a reduced ATP content. Culture of monocytes, isolated from healthy individuals, and differentiated into polarized M1 macrophages, together with a cytokine mixture (IL-1{beta}, IFN-{gamma}, and TNF-), to mimic the inflammatory cytokine storm, for 24 h markedly increased VDAC1 and Monocyte chemoattractant protein-1 (MCP-1) release in culture medium. The presence of the cytokine mixture reduced the ATP content, cell viability, and the phagocytic capability of macrophages. Co-staining of VDAC1 and the plasma membrane marker Na+/K+-ATPase showed that cytokine-treatment mistargeted VDAC1 to the cell surface of macrophages. All these effects were prevented by VDAC1 inhibition using VBIT-4, VDAC1-specific antibody (VDAC1-ab), or metformin. Our findings indicate that increased VDAC1 expression and cell surface mistargeting in immune cells might be associated with cell dysfunction, potentially contributing to the severity of COVID-19 infection. The data also indicate serum VDAC1 as a biomarker of COVID-19 severity and the use of VDAC1 inhibitors as potential drug candidates restoring macrophages and PBMCs function in individuals severely affected by COVID-19.

pathology↗

bioRxiv2023

Identification of an osteopontin-derived peptide that binds neuropilin-1 and activates vascular cells

BackgroundThe osteopontin-derived peptide FOL-005 has been shown to stimulate hair growth. Using ligand-receptor glycocapture technology we identified neuropilin-1 (NRP-1), a known co-receptor for vascular endothelial growth factor (VEGF) receptors, as the most probable receptor for FOL-005. Considering that induction of perifollicular angiogenesis by VEGF is a critical step in activation of the anagen growth phase of hair follicles, we investigated the effect of the more stable FOL-005 analogue FOL-026 on vascular cells. MethodsX-ray diffraction and microscale thermophoresis analysis were used to determine receptor binding of FOL-peptides. Cultured human arterial smooth muscle cells were used for studies of cell proliferation, migration, intracellular signaling, and apoptosis. A Matrigel plug assay was used to study angiogenesis in vivo. RNA seq. was used to analyze changes in gene expression patterns. ResultsFOL-026 was found to share binding site with VEGF in the NRP-1 b1-subdomain. Stimulation of human umbilical vein endothelial cells with FOL-026 resulted in phosphorylation of AKT and ERK1/2, increased cell growth and migration, stimulation of endothelial tube formation and inhibition of apoptosis in vitro, as well as activation of angiogenesis in vivo. Down-regulation of NRP-1 by NRP-1-specific small interfering RNA blocked the stimulatory effects of FOL-026 on endothelial cells. RNA sequencing showed that FOL-026 activated pathways involved in tissue repair. Exposure of human coronary artery smooth muscle cells to FOL-026 stimulated cell proliferation, migration, inhibited apoptosis, and induced VEGF gene expression by an NRP-1-dependent mechanism. ConclusionsThese findings identify NRP-1 as the receptor for FOL-026 and show that its biological effects mimic that of growth factors binding to the VEGF receptor family. They also suggest that FOL-026 may have therapeutical potential in conditions that require vascular repair and / or enhanced angiogenesis. Clinical perspectiveO_LIInsufficient vascular repair increases the risk of acute cardiovascular events, something that is of particular importance in diabetes. C_LIO_LIA peptide derived from the extracellular matrix protein osteopontin (FOL-026) binds to the vascular endothelial growth factor (VEGF) co-receptor neuropilin-1 stimulating endothelial and vascular smooth muscle cell proliferation and migration as well as the formation of new vessels. C_LIO_LIBy mimicking the effects of VEGF FOL-026 may have therapeutical potential in conditions that require vascular repair and / or enhanced angiogenesis such as vascular complications to diabetes, peripheral artery disease and salvage of ischemic myocardium. C_LI

cell biology↗