ATR1 A1166C (rs5186), FII G20210A (rs1799963), FV G1691A (rs6025), FXIII 97G > T (rs11466016) and MTHFR A1298C (rs1801131) polymorphisms and the risk of ST-elevation myocardial infarction in young Mexican individuals.

BACKGROUND: Previous studies had identified genetic variants associated with Myocardial Infarction, but results are inconclusive. We examined the association between FII G20210A (rs1799963), FV G1691A (rs6025), FXIII 97G > T (rs11466016), ATR1 A1166C (rs5186) and MTHFR A1298C (rs1801131) polymorphisms and ST elevation Myocardial Infarction in young Mexican individuals. METHODS: We included a total of 350 patients with Myocardial Infarction <45 years old and 350 controls matched by age and gender. The polymorphisms were analyzed by PCR-RFLP using specific restriction enzymes. DNA fragments were separated by electrophoresis in 2% gel of agarose and visualized using SYBR green. RESULTS: The A1166C (p = 0.004) but not FXIII 97G > T (p = 0.19), G20210A (p = 0.32), G1691A (p = No significant) and A1298C (p = 0.21) polymorphisms were associated with increased risk for ST elevation Myocardial Infarction. Moreover, dyslipidemia, hypertension, smoking and family history of atherothrombotic disease were associated. CONCLUSIONS: We found that A1166C represented increased risk for ST elevation Myocardial Infarction. However, G20210A, G1691A, 97G > T, and A1298C were not associated. In addition, we had determined that Glu298Asp, PLA1/A2, TAFI Thr325Ile, ACE I/D, AGT M235T and PAI-1 4G/5G polymorphisms represented increased risk in the same group of patients. However, MTHFR C677T, AGT T174M, FV G1691A, TSP-1 N700S, MTHFR C677T and TAFI 174 M polymorphisms were no associated. Our results suggest that in young patients with ST Myocardial Infarction, those polymorphisms could contribute to premature endothelial dysfunction, atherothrombosis, vasoconstriction, increased platelet aggregation, muscle cell migration and proliferation. Further studies are required to try to better assess gene-gene and gene-modifiable factors interaction.

A Narrative Review of the Renin-Angiotensin-Aldosterone System in the Placenta and Placental Bed of HIV Infected Women of African Ancestry with Preeclampsia.

PURPOSE OF REVIEW: Both HIV infection and preeclampsia (PE), a pregnancy-specific disorder of hypertension and multi-system organ involvement, have high prevalence rates especially in low-to-middle-income countries. The immunoexpression of specific renin-angiotensin-aldosterone system (RAAS) receptors in the placenta and placental bed interface may forecast the risk of PE. RECENT FINDINGS: Preeclampsia is a leading risk factor for mortality worldwide and remains a challenge in HIV-infected individuals especially those on antiretroviral therapy (ART). Irregular RAAS stimulation may be linked to the pathophysiology of hypertension in HIV infection and in PE. The AT1 receptor is expressed across all trimesters of pregnancy, within placental tissue, eliciting vasoconstriction. This increased expression is associated with the severity of PE, implying that the increased expression may be involved in the pathogenesis of this pregnancy disorder. The AT2 receptor expression in normotensive pregnancies was shown to be lower as compared to non-pregnant individuals. Furthermore, in the PE placental bed, the AT2 receptor is the predominant receptor subtype and is found in extravillous trophoblast cells where they facilitate vasodilation. However, AT4R in placentae of PE pregnancies are found to be significantly reduced compared to normotensives pregnancies. The data on the role played by the RAAS pathway in pregnancy is conflicting. Investigation into a tissue-based RAAS with emphasis on immune-expression within the placenta and placental bed may help resolve this conundrum.

Computational biophysical characterization of the SARS-CoV-2 spike protein binding with the ACE2 receptor and implications for infectivity.

SARS-CoV-2 is a novel highly virulent pathogen which gains entry to human cells by binding with the cell surface receptor - angiotensin converting enzyme (ACE2). We computationally contrasted the binding interactions between human ACE2 and coronavirus spike protein receptor binding domain (RBD) of the 2002 epidemic-causing SARS-CoV-1, SARS-CoV-2, and bat coronavirus RaTG13 using the Rosetta energy function. We find that the RBD of the spike protein of SARS-CoV-2 is highly optimized to achieve very strong binding with human ACE2 (hACE2) which is consistent with its enhanced infectivity. SARS-CoV-2 forms the most stable complex with hACE2 compared to SARS-CoV-1 (23% less stable) or RaTG13 (11% less stable). Notably, we calculate that the SARS-CoV-2 RBD lowers the binding strength of angiotensin 2 receptor type I (ATR1) which is the native binding partner of ACE2 by 44.2%. Strong binding is mediated through strong electrostatic attachments with every fourth residue on the N-terminus alpha-helix (starting from Ser19 to Asn53) as the turn of the helix makes these residues solvent accessible. By contrasting the spike protein SARS-CoV-2 Rosetta binding energy with ACE2 of different livestock and pet species we find strongest binding with bat ACE2 followed by human, feline, equine, canine and finally chicken. This is consistent with the hypothesis that bats are the viral origin and reservoir species. These results offer a computational explanation for the increased infection susceptibility by SARS-CoV-2 and allude to therapeutic modalities by identifying and rank-ordering the ACE2 residues involved in binding with the virus.

Angiotensin II inhibits P-glycoprotein in intestinal epithelial cells.

AIM: P-glycoprotein (Pgp/MDR1) plays a major role in intestinal homeostasis. Decrease in Pgp function and expression has been implicated in the pathogenesis of IBD. However, inhibitory mechanisms involved in the decrease of Pgp in inflammation are not fully understood. Angiotensin II (Ang II), a peptide hormone predominantly expressed in the epithelial cells of the crypt-villus junction of the intestine, has been shown to exert pro-inflammatory effects in the gut. It is increased in IBD patients and animals with experimental colitis. Whether Ang II directly influences Pgp is not known. METHODS: Pgp activity was measured as verapamil-sensitive 3 H-digoxin flux. Pgp surface expression and exocytosis were measured by cell surface biotinylation studies. Signalling pathways were elucidated by Western blot analysis and pharmacological approaches. RESULTS: Ang II (10 nM) significantly inhibited Pgp activity at 60 minutes. Ang II-mediated effects on Pgp function were receptor-mediated as the Ang II receptor 1 (ATR1) antagonist, losartan, blocked Pgp inhibition. Ang II effects on Pgp activity appeared to be mediated via PI3 kinase, p38 MAPK and Akt signalling. Ang II-mediated inhibition of Pgp activity was associated with a decrease in the surface membrane expression of Pgp protein via decreased exocytosis and was found to be dependent on the Akt pathway. Short-term treatment of Ang II (2 mg/kg b.wt., 2 hours) to mice also decreased the membrane expression of Pgp protein levels in ileum and colon. CONCLUSION: Our findings provide novel insights into the role of Ang II and ATR1 in decreasing Pgp expression in intestinal inflammation.

Análise Dopplerfluxométrica e angiogênica de tumores mamários caninos / Dopplerfluxometric and angiogenic analysis of canine mammary tumors

Foi avaliado o comportamento de índices Doppler e a expressão de genes relacionados à neovascularização tumoral, visando caracterizar a vascularização das massas neoplásicas. Foram utilizadas 27 cadelas, com diagnóstico histopatológico de neoplasia mamária, sendo submetidas à avaliação Dopplerfluxométrica tumoral e à coleta de fragmentos neoplásicos para análise de expressão gênica de VEGF, FLT-1, FLK-1 e ATR1. Foram encontrados 22 tumores de origem epitelial (carcinomas) e cinco de origem mesenquimal (sarcomas). Observou-se correlação positiva entre o FLT-1 e as variáveis PS, PI e RI. O FLK-1 apresentou correlação igualmente positiva com os parâmetros PS e PI e uma tendência para RI, enquanto o VEGF retratou correlação positiva apenas com IP. O VEGF também mostrou correlação positiva com seus receptores, porém não apresentou correlação com o ATR1. O FLT-1 e o FLK-1 apresentaram ainda correlação positiva entre si e com o ATR1. Houve maior expressão média do VEGF nos tumores epiteliais do que nos mesenquimais. As variáveis PS, PI e RI, associadas com a expressão do VEGF e seus receptores, mostraram-se relevantes para caracterizar a neovascularização de tumores malignos, e a expressão diferenciada do VEGF entre os tipos tumorais pode ser um indicador auxiliar na caracterização de neoplasias mamárias malignas em cadelas.(AU)

The behavior of the tumor Doppler indexes and gene expression related to neovascularization was evaluated aiming to improve the characterization of neoplastic masses vascularization. Twenty-seven bitches with histopathological diagnosis of mammary neoplasia were submitted to tumor Dopplerfluxometric evaluation and collection of neoplastic fragments to analyze the gene expression of VEGF, FLT-1, FLK-1 and ATR1. Were found 22 epithelial (carcinomas) and five mesenchymal (sarcomas) tumors. Positive correlation was observed between FLT-1 and PS, PI and RI. FLK-1 presented a similar positive correlation with the PS and PI parameters, and a tendency for RI (r= 0.45, P= 0.07), whereas VEGF showed a positive correlation just with PI. VEGF also showed a positive correlation with its receptors, but did not present a correlation with ATR1. FLT-1 and FLK-1 also showed positive correlation with each other, and with ATR1. There was higher mean expression of VEGF in epithelial tumors than in mesenchymal ones. The PS, PI and RI associated with the expression of VEGF and its receptors have been shown to be relevant to characterize neovascularization of malignant tumors, and the differentiated expression of VEGF between the types of mammary tumors, may be an auxiliary indicator in the characterization of malignant breast cancers in bitches.(AU)

The renin-angiotensin system: a possible new target for depression.

Depression remains a debilitating condition with an uncertain aetiology. Recently, attention has been given to the renin-angiotensin system. In the central nervous system, angiotensin II may be important in multiple pathways related to neurodevelopment and regulation of the stress response. Studies of drugs targeting the renin-angiotensin system have yielded promising results. Here, we review the potential beneficial effects of angiotensin blockers in depression and their mechanisms of action. Drugs blocking the angiotensin system have efficacy in several animal models of depression. While no randomised clinical trials were found, case reports and observational studies showed that angiotensin-converting enzyme inhibitors or angiotensin receptor blockers had positive effects on depression, whereas other antihypertensive agents did not. Drugs targeting the renin-angiotensin system act on inflammatory pathways implicated in depression. Both preclinical and clinical data suggest that these drugs possess antidepressant properties. In light of these results, angiotensin system-blocking agents offer new horizons in mood disorder treatment.

Cell-Free Production of Pentacyclic Triterpenoid Compound Betulinic Acid from Betulin by the Engineered Saccharomyces cerevisiae.

Betulinic acid is a product of plant secondary metabolism which has shown various bioactivities. Several CYP716A subfamily genes were recently characterized encoding multifunctional oxidases capable of C-28 oxidation. CYP716A12 was identified as betulin C-28 oxidase, capable of modifying betulin. This study aimed to induce the transformation of betulin to betulinic acid by co-expressing enzymes CYP716A12 from Medicago truncatula and ATR1 from Arabidopsis thaliana in Saccharomyces cerevisiae. The microsome protein extracted from the transgenic yeast successfully catalyzed the transformation of betulin to betulinic acid. We also characterized the optimization of cell fragmentation, protein extraction method, and the conversion conditions. Response surface methodology was implemented, and the optimal yield of betulinic acid reached 18.70%. After optimization, the yield and the conversion rate of betulin were increased by 83.97% and 136.39%, respectively. These results may present insights and strategies for the sustainable production of betulinic acid in multifarious transgenic microbes.

Structurally distinct Arabidopsis thaliana NLR immune receptors recognize tandem WY domains of an oomycete effector.

Nucleotide-binding leucine-rich repeat (NB-LRR, or NLR) receptors mediate pathogen recognition. The Arabidopsis thaliana NLR RPP1 recognizes the tandem WY-domain effector ATR1 from the oomycete Hyaloperonospora arabidopsidis through direct association with C-terminal LRRs. We isolated and characterized homologous NLR genes RPP1-EstA and RPP1-ZdrA from two Arabidopsis ecotypes, Estland (Est-1) and Zdarec (Zdr-1), responsible for recognizing a novel spectrum of ATR1 alleles. RPP1-EstA and -ZdrA encode nearly identical NLRs that are phylogenetically distinct from known immunity-activating RPP1 homologs and possess greatly expanded LRR domains. Site-directed mutagenesis and truncation analysis of ATR1 suggests that these homologs recognize a novel surface of the 2(nd) WY domain of ATR1, partially specified by a C-terminal region of the LRR domain. Synteny comparison with RPP1 loci involved in hybrid incompatibility suggests that these functions evolved independently. Closely related RPP1 homologs have diversified their recognition spectra through LRR expansion and sequence variation, allowing them to detect multiple surfaces of the same pathogen effector. Engineering NLR receptor specificity may require a similar combination of repeat expansion and tailored amino acid variation.

Calcium, TRPC channels, and regulation of the actin cytoskeleton in podocytes: towards a future of targeted therapies.

With more than 6,000 new pediatric patients with treatment-resistant nephrotic syndrome in the US each year alone, the unmet need for novel, podocyte-specific therapies is substantial. Recently, the established therapeutic benefit of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB) was used as a starting point to gain insight into the pathomechanism of primary podocytopathies. A calcium (Ca(2+))-mediated pathway has been identified that connects the angiotensin type 1 receptor (AT1R) to podocyte cytoskeletal dynamics, essential for a functioning glomerular filtration barrier. This discovery provided an important missing piece in our understanding of the pathomechanism of filter barrier damage, revealing Ca(2+) signaling as critical for podocyte health and disease. The identification of the two Ca(2+) permeant channels TRPC5 and TRPC6 as mediators of this pathway not only bolstered the importance of podocyte cytoskeleton dynamics but also revealed promising drug targets for treatment-resistant nephrotic syndrome. This review will focus on this novel signaling pathway in primary podocytopathies and its implications for next-generation therapies for glomerular disease.