Biology subjects

Gamez, M.

Publications and source records attributed to Gamez, M..

5 recordsLinked to original sources

bioRxiv2025

Matrix Metalloproteinase (MMP) inhibition rescues endothelial glycocalyx damage and reduces neutrophil infiltration in sepsis-associated acute kidney injury

Endothelial glycocalyx (eGlx), a carbohydrate-rich endothelial coat, maintains vascular homeostasis, and its disruption contributes to several vascular diseases. We previously identified matrix metalloproteinase (MMP) 2 and 9-mediated eGlx shedding as a key mechanism in human glomerular endothelial cell (GEnC) damage and kidney dysfunction in diabetes. Here, we sought to determine whether this mechanism contributes to renal and systemic microvascular endothelial cell injury in sepsis-AKI. Sepsis-AKI was induced in mice by lipopolysaccharide (LPS) injection. Confocal microscopy demonstrated glomerular and peritubular eGlx damage, and increased circulating SDC4 demonstrated systemic eGlx shedding. These were associated with enhanced mRNA expression of eGlx components (syndecans 1 and 4) and endothelial inflammatory markers, Intercellular and Vascular Cell Adhesion Molecules (ICAM and VCAM) in the kidney. Additionally, sepsis-AKI markers, serum creatinine and urea, were increased. We found that renal and circulating MMP9, but not MMP2, levels were raised in sepsis-AKI. Moreover, MMP9 staining colocalises with neutrophil, endothelial and mesangial staining in glomeruli in sepsis-AKI. Treatment with MMP2 and 9 inhibitor 1, 1h before LPS injection, prevented glomerular, peritubular and systemic eGlx damage in sepsis-AKI. MMP inhibition also attenuated glomerular leucocyte numbers in sepsis-AKI. We confirmed increased MMP9 activity, shedding of eGlx syndecan 1 and elevated angiopoietin 2 levels, an endothelial damage marker, in sepsis-AKI in humans. Moreover, we used human glomerular endothelial cells (GEnC) in vitro to demonstrate that human sepsis-AKI serum directly damages GEnC eGlx. Our studies confirm that MMP-mediated eGlx damage is a key contributor to renal and systemic microvascular dysfunction in sepsis-AKI and represents a potential therapeutic target for protecting the microvasculature.

cell biology↗

bioRxiv2025

Effects of Three Natural Dietary Compounds on Insect Pests

Effective and sustainable pest management is a critical challenge in agriculture. This study evaluated the relative efficacy of three natural compounds --neem oil, boric acid, and gallotannin acid-- against larvae of three pest species: Rhynchophorus ferrugineus (F.) (red palm weevil), Plodia interpunctella (Hubner) (Indian meal moth), and Spodoptera exigua (Hubner) (beet armyworm). Laboratory bioassays revealed distinct differences in larval survival and mortality across the species. Neem oil demonstrated high effectiveness against S. exigua larvae, achieving 100% mortality at all tested dietary concentrations, and moderate effectiveness against R. ferrugineus. In contrast, it had no significant effect on P. interpunctella. Boric acid was proved to be universally effective, leading to 100% mortality in all three species at the highest concentration. Gallotannin acid had species-specific effects on S. exigua but had negligible effects on R. ferrugineus and P. interpunctella. These findings highlight the potential of natural, low-toxicity compounds as alternatives to synthetic insecticides. Additionally, this study suggests new frontiers for investigating the role of the gut microbiota in mediating the effectiveness of these compounds. While the results provide promising insights into environmentally friendly pest control strategies, further research, including field trials and microbiological assessments, is needed to fully validate their application in agricultural settings. This work contributes to advancing sustainable pest management practices that reduce environmental impact while addressing critical agricultural needs.

zoology↗

bioRxiv2023

Inhibition of MMP 2 protects the endothelial glycocalyx and improves diastolic function in diabetic cardiomyopathy

The coronary microvascular endothelial glycocalyx (EGlx) is a vital regulator of vascular permeability and EGlx damage contributes to the development of diabetic cardiomyopathy. Matrix metalloproteinases 2 and 9 (MMP2/9) have been identified as key enzymes in the degradation of EGlx components, notably syndecan 4 (SDC4), and are upregulated in diabetes. We tested the hypothesis that inhibition of MMP2/9 can protect the EGlx and improve diastolic function in diabetic cardiomyopathy. Type 1 diabetes was induced in FVB mice by streptozotocin (STZ) injections. Mice were treated with daily injections of the MMP2/9 inhibitor, SB-3CT, for 2 weeks from 7 weeks post STZ. Echocardiography was utilised to assess heart function and lectin staining for the measurement of EGlx depth. Immunolabelling of heart sections for albumin provided an indication of albumin extravasation. A mechanism of EGlx shedding was investigated in vitro in human coronary microvascular endothelial cells treated with TNF- and SB-3CT. Diabetic mice developed diastolic dysfunction from 6 weeks post STZ. MMP2/9 inhibition reversed diastolic dysfunction, EGlx thinning and albumin extravasation in diabetic animals. In vitro, TNF- caused an increase in MMP9 activity and SDC4 shedding from human coronary microvascular endothelial cells. Treatment with SB-3CT reduced MMP9 activity and prevented SDC4 shedding. Knockdown of MMP9 expression prevented TNF- induced SDC4 shedding. This study demonstrates MMP2/9 inhibition as a strategy to protect the EGlx and improve diastolic function in diabetic cardiomyopathy. Our findings suggest new avenues for therapeutic interventions in cardiovascular complications associated with diabetes. Statements and DeclarationsO_ST_ABSCompeting interestsC_ST_ABSThe authors have no competing interests to declare that are relevant to the content of this article.

physiology↗

bioRxiv2021

Pathogenic tau disrupts the cellular program that maintains neuronal identity

Neurons in human Alzheimers disease acquire phenotypes that are also present in various cancers, including over-stabilization of the cytoskeleton, nuclear pleomorphism, decondensation of constitutive heterochromatin, and aberrant activation of the cell cycle. Unlike in cancer, in which cell cycle activation drives tumor formation, activation of the cell cycle in post-mitotic neurons is sufficient to induce neuronal death. Multiple lines of evidence suggest that abortive cell cycle activation is a consequence of pathogenic forms of tau, a protein that drives neurodegeneration in Alzheimers disease and related "tauopathies." We have combined network analysis of human Alzheimers disease and mouse tauopathy with mechanistic studies in Drosophila to discover that pathogenic forms of tau drive abortive cell cycle activation by disrupting the cellular program that maintains neuronal identity. Mechanistically, we identify Moesin, a prognostic biomarker for cancer and mediator of the epithelial-mesenchymal transition (EMT), as a major effector of tau-induced neurotoxicity. We find that aberrant activation of Moesin in neurons acts through the actin cytoskeleton to dysregulate the cellular program that maintains neuronal identity. Our study identifies mechanistic parallels between tauopathy and cancer and sets the stage for novel therapeutic approaches.

neuroscience↗

bioRxiv2020

The SARS-CoV-2 spike protein disrupts the cooperative function of human cardiac pericytes - endothelial cells through CD147 receptor-mediated signalling: a potential non-infective mechanism of COVID-19 microvascular disease

Severe coronavirus disease 2019 (COVID-19) manifests as a life-threatening microvascular syndrome. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses the Spike (S) protein to engage with its receptors and infect host cells. To date, it is still not known whether heart vascular pericytes (PCs) are infected by SARS-CoV-2, and if the S protein alone provokes PC dysfunction. Here, we aimed to investigate the effects of the S protein on primary human cardiac PC signalling and function. Results show, for the first time, that cardiac PCs are not permissive to SARS-CoV-2 infection in vitro, whilst a recombinant S protein alone elicits functional alterations in PCs. This was documented as: (1) increased migration, (2) reduced ability to support endothelial cell (EC) network formation on Matrigel, (3) secretion of pro-inflammatory molecules typically involved in the cytokine storm, and (4) production of pro-apoptotic factors responsible for EC death. Next, adopting a blocking strategy against the S protein receptors angiotensin-converting enzyme 2 (ACE2) and CD147, we discovered that the S protein stimulates the phosphorylation/activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) through the CD147 receptor, but not ACE2, in PCs. The neutralisation of CD147, either using a blocking antibody or mRNA silencing, reduced ERK1/2 activation and rescued PC function in the presence of the S protein. In conclusion, our findings suggest that circulating S protein prompts vascular PC dysfunction, potentially contributing to establishing microvascular injury in organs distant from the site of infection. This mechanism may have clinical and therapeutic implications. Clinical perspectiveO_LISevere COVID-19 manifests as a microvascular syndrome, but whether SARS-CoV-2 infects and damages heart vascular pericytes (PCs) remains unknown. C_LIO_LIWe provide evidence that cardiac PCs are not infected by SARS-CoV-2. Importantly, we show that the recombinant S protein alone elicits cellular signalling through the CD147 receptor in cardiac PCs, thereby inducing cell dysfunction and microvascular disruption in vitro. C_LIO_LIThis study suggests that soluble S protein can potentially propagate damage to organs distant from sites of infection, promoting microvascular injury. Blocking the CD147 receptor in patients may help protect the vasculature not only from infection, but also from the collateral damage caused by the S protein. C_LI

cell biology↗