Biology subjects

Martinez de la Escalera, G.

Publications and source records attributed to Martinez de la Escalera, G..

5 recordsLinked to original sources

bioRxiv2024

Vasoinhibin is Generated by the Renin-Angiotensin System

Vasoinhibin is a fragment of the hormone prolactin (PRL) that inhibits angiogenesis, vasopermeability, and vasodilation. Cathepsin D (CTSD) cleaves the N-teminal of PRL to generate vasoinhibin in the retina of neonate mice as revealed by the CTSD inhibitor, pepstatin A (PA). However, PA also inhibits renin. Because renin is expressed in the retina and the renin-angiotensin system (RAS) gives rise to peptides with positive and negative effects on blood vessel growth and function, we investigated whether renin cleaves PRL to vasoinhibin in the newborn mouse retina and in the circulation. Newborn mouse retinal extracts from wild-type and CTSD-null newborn mice cleaved PRL to a 14 kDa vasoinhibin and such cleavage was prevented by heat-inactivation, PA, and the selective renin inhibitor VTP-27999 suggesting the contribution of renin. In agreement, recombinant renin cleaved different species PRLs to the expected 14 kDa vasoinhibin, a mass consistent with a consensus renin cleavage site located at Leu124-Leu125 in rat and mouse PRLs and at Leu126-Leu127 in human, bovine, and ovine PRLs. Dehydration and rehydration (D/R) in rats increased the levels of renin and PRL in plasma. Further increase in PRL circulating levels by the dopamine D2 receptor blocker, sulpiride, enabled detection of 14 kDa vasoinhibin in D/R rats. Moreover, the incubation of PRL with plasma from D/R rats generated a 14 kDa vasoinhibin that was prevented by VTP-27999. These findings add renin to the list of PRL-cleaving proteases and introduce vasoinhibin as a RAS-mediated mechanism for regulating blood vessel growth and function.

physiology↗

bioRxiv2024

Topical Ophthalmic Administration of VIAN-c4551 Antiangiogenic Peptide for Diabetic Macular Edema: Preclinical Efficacy and Ocular Pharmacokinetics

VIAN-c4551 is a cyclic antiangiogenic peptide that stands as a potent and stable inhibitor of vascular endothelial cell growth factor (VEGF), the major vasopermeability and angiogenic factor in diabetic macular edema and diabetic retinopathy. Intravitreal injections of inhibitors of VEGF are a first-line therapy, but the invasiveness, risk, and low adherence of frequent intravitreal injections interfere with the needed long-term treatments and successful outcomes. Eye drops are non-invasive and favor compliance. Here, we evaluated the preclinical efficacy, permeability, and ocular pharmacokinetics of VIAN-c4551 delivered in eye drops. VIAN-c4551 demonstrated high potency (IC50 = 137 pM) to inhibit the permeability of human umbilical vein endothelial cell monolayers induced by VEGF. VIAN-c4551 eye drops potently (0.005% minimum effective dose) prevented the retinal vascular leakage induced by VEGF injected intravitreally for up to 24 hours and reversed the increase in retinal vascular permeability due to streptozotocin-induced diabetes in rats and mice. VIAN-c4551 exhibited high permeability across MDCK epithelium and, after a single topical ocular instillation in rabbits, reached the retina-choroid in micromolar concentrations several orders of magnitude above its IC50 (Cmax= 51 {micro}M at 6 hours) that lasted at least 24 hours. In conclusion, VIAN-c4551 eye drops reach the back of the eye at therapeutic concentrations, providing a potential, once-a-day, non-invasive intervention for preventing and reversing retinal vascular leakage in diabetic macular edema, diabetic retinopathy, and other vascular retinopathies and preserving sight.

pharmacology and toxicology↗

bioRxiv2023

The apoptotic, inflammatory, and fibrinolytic actions of vasoinhibin are in a motif different from its antiangiogenic HGR motif

Vasoinhibin is a proteolytic fragment of the hormone prolactin that inhibits blood vessel growth (angiogenesis) and permeability, stimulates the apoptosis and inflammation of endothelial cells and promotes fibrinolysis. The antiangiogenic and antivasopermeability properties of vasoinhibin were recently traced to the HGR motif located in residues 46 to 48, allowing the development of potent, orally active, HGR-containing vasoinhibin analogs for therapeutic use against angiogenesis-dependent diseases. However, whether the HGR motif is also responsible for the apoptotic, inflammatory, and fibrinolytic properties of vasoinhibin has not been addressed. Here, we report that HGR-containing analogs are devoid of these properties. Instead, the incubation of human umbilical vein endothelial cells with oligopeptides containing the sequence HNLSSEM, corresponding to residues 30 to 36 of vasoinhibin, induced apoptosis, the nuclear translocation of NF-{kappa}B, the expression of genes encoding leukocyte adhesion molecules (VCAM1 and ICAM1) and proinflammatory cytokines (IL1B, IL6, TNF), and the adhesion of peripheral blood leukocytes. Also, the intravenous or intra-articular injection of HNLSSEM-containing oligopeptides induced the expression of Vcam1, Icam1, Il1b, Il6, Tnf in the lung, liver, kidney, eye, and joints of mice and, like vasoinhibin, these oligopeptides promoted the lysis of plasma fibrin clots by binding to plasminogen activator inhibitor-1 (PAI-1). Moreover, the inhibition of PAI-1, urokinase plasminogen activator receptor, or NF-{kappa}B prevented the apoptotic and inflammatory actions. In conclusion, the functional properties of vasoinhibin are segregated into two different structural determinants. Because apoptotic, inflammatory, and fibrinolytic actions may be undesirable for antiangiogenic therapy, HGR-containing vasoinhibin analogs stand as selective and safe agents for targeting pathological angiogenesis.

cell biology↗

bioRxiv2021

The spike protein of SARS-CoV-2 induces endothelial inflammation through integrin α5β1 and NF-κB

Vascular endothelial cells (EC) form a critical interface between blood and tissues that maintains whole-body homeostasis. In COVID-19, disruption of the EC barrier results in edema, vascular inflammation, and coagulation, the hallmarks of the severe disease. However, the mechanisms by which EC are dysregulated in COVID-19 are unclear. Here, we show that the spike protein of SARS-CoV-2 alone activates the EC inflammatory phenotype in a manner dependent on integrin 5{beta}1 signaling. Incubation of human umbilical vein EC with whole spike, its receptor-binding domain, or the integrin-binding tripeptide RGD induced the nuclear translocation of NF-{kappa}B and enhanced the expression of leukocyte adhesion molecules VCAM1 and ICAM1, the adhesion of peripheral blood leukocytes, and the permeability of the monolayer. Inhibitors of integrin 5{beta}1 activation prevented these effects. We suggest that the spike protein, through its RGD motif in the receptor-binding domain, binds to integrin 5{beta}1 in EC to activate Rho GTPases, eNOS pathways, and the NF-{kappa}B gene expression program responsible for vascular leakage and leukocyte infiltration, respectively. These findings uncover a new direct action of SARS-CoV-2 on EC dysfunction and introduce integrin 5{beta}1 as a promising target for treating vascular inflammation in COVID-19.

cell biology↗

bioRxiv2019

Genotyping and functional regression trees reveals environmental preferences of toxic cyanobacteria (Microcystis aeruginosa complex) along a wide spatial gradient

Addressing ecological and evolutionary processes explaining biodiversity patterns is essential to identify the mechanisms driving community assembly. In the case of bacteria, the formation of new ecologically distinct populations or ecotypes is proposed as one of the main drivers of diversification. New ecotypes arise when mutation in key functional genes or acquisition of new metabolic pathways by horizontal gene transfer allow the population to exploit new resources, making possible their coexistence with parental population. Recently, we have reported the presence of toxic, microcystin-producing organisms from the Microcystis aeruginosa complex (MAC) through a wide environmental gradient (800 km) in South America, ranging from freshwater to estuarine-marine waters. In order to explain this finding, we hypothesize that the success of toxic organisms of MAC in such array of environmental conditions is due to the existence of ecotypes having different environmental preferences. So, we analysed the genetic diversity of microcystin-producing populations of Microcystis aeruginosa complex (MAC) by qPCR and high resolution melting analysis (HRMA) of a functional gene (mcyJ, involved in microcystin synthesis) and explored its relationship with the environmental conditions through the gradient by functional classification and regression trees (fCART). Six groups of mcyJ genotypes were distinguished and selected by different combinations of water temperature, conductivity and turbidity, determining the environmental preferences of each group. Since these groups were based on the basis of similar sequence and ecological characteristics they were defined as ecotypes of toxic MAC. Taking into account that the role of microcystins in MAC biology and ecology has not yet been elucidated, we propose that the toxin might have a role in MAC fitness that would be mainly controlled by the physical environment in a way such that the ecotypes that thrive in the riverine zone of the gradient would be more stable and less influenced by salinity fluctuations than those living at the marine limit of the estuary. These would periodically disappear or being eliminated by salinity increases, depending on the estuary dynamics. Thus, ecotypes generation would be an important mechanism allowing toxic MAC adapting to and succeed in a wide array of environmental conditions.

ecology↗