Search

People with comorbidities and the male sex are at a higher risk of developing severe COVID-19. In the present study, we aim to investigate the associated factors for infection, severity, and death due to COVID-19 in a population from Nuevo León, México. Epidemiological COVID-19 data were collected from 65 hospitals from December 2020 to May 2022. A total of 75,232 cases were compiled from which 25,722 cases were positive for SARS-CoV-2. Male sex, older age, diabetes, obesity, and hypertension were associated with infection. In addition to the above-mentioned factors, renal disease, cardiovascular disease, and immunosuppression were found to be associated with increased COVID-19 severity. These factors, as well as neurological diseases, are also associated with death due to COVID-19. When comparing the different variants of SARs-CoV-2, the variant B1.1.519 increased the probability of death by 2.23 times compared to the AY.20 variant. Male sex, older age, diabetes, obesity, and hypertension are associated with SARS-CoV-2 infection, severity, and death. Along with the aforementioned comorbidities, renal disease, cardiovascular disease, and immunosuppression are also associated with severity and death. Another factor associated with death is the presence of neurological disease. The SARS-CoV-2 B1.1.519 variant increases the odds of death compared to the SARS-CoV-2 AY.20 variant. [ABSTRACT FROM AUTHOR]

Background: The generation of induced pluripotent stem cells has opened the field of study for stem cell research, disease modeling and drug development. However, the epigenetic signatures present in somatic cells make cell reprogramming still an inefficient process. This epigenetic memory constitutes an obstacle in cellular reprogramming. Here, we report the effect of hydralazine (HYD) and valproic acid (VPA), two small molecules with proven epigenetic activity, on the expression of pluripotency genes in adult (aHF) and neonatal (nbHF) human fibroblasts. Methods: aHF and nbHF were treated with HYD and/or VPA, and viability and gene expression assays for OCT4, NANOG, c-MYC, KLF4, DNMT1, TET3, ARID1A and ARID2 by quantitative PCR were performed. aHF and nbHF were transfected with episomal plasmid bearing Yamanaka factors (OCT4, SOX2, KLF4 and c-MYC) and exposed to HYD and VPA to determine the reprogramming efficiency. Methylation sensitive restriction enzyme (MSRE) qPCR assays were performed on OCT4 and NANOG promoter regions. Immunofluorescence assays were carried out for pluripotency genes on iPSC derived from aHF and nbHF. Results: HYD upregulated the expression of OCT4 (2.5-fold) and NANOG (fourfold) genes but not c-Myc or KLF4 in aHF and had no significant effect on the expression of all these genes in nbHF. VPA upregulated the expression of NANOG (twofold) in aHF and c-MYC in nbHF, while it downregulated the expression of NANOG in nbHF. The combination of HYD and VPA canceled the OCT4 and NANOG overexpression induced by HYD in aHF, while it reinforced the effects of VPA on c-Myc expression in nbHF. The HYD-induced overexpression of OCT4 and NANOG in aHDF was not dependent on demethylation of gene promoters, and no changes in the reprogramming efficiency were observed in both cell populations despite the downregulation of epigenetic genes DNMT1, ARID1A, and ARID2 in nbHF. Conclusions: Our data provide evidence that HYD regulates the expression of OCT4 and NANOG pluripotency genes as well as ARID1A and ARID2 genes, two members of the SWI/SNF chromatin remodeling complex family, in normal human dermal fibroblasts. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is among the main causes of death by cancer worldwide, representing about 80–90% of all liver cancers. Treatments available for advanced HCC include atezolizumab, bevacizumab, sorafenib, among others. Atezolizumab and bevacizumab are immunological options recently incorporated into first-line treatments, along with sorafenib, for which great treatment achievements have been reached. However, sorafenib resistance is developed in most patients, and therapeutical combinations targeting cancer hallmark mechanisms and intracellular signaling have been proposed. In this review, we compiled evidence of the mechanisms of cell death caused by sorafenib administered alone or in combination with valproic acid and metformin and discussed them from a molecular perspective. [ABSTRACT FROM AUTHOR]

Mycobacteria are microorganisms distributed in the environment worldwide, and some of them, such as Mycobacterium tuberculosis or M. leprae , are pathogenic. The hydrophobic mycobacterial cell envelope has low permeation and bacteria need to export products across their structure. Mycobacteria possess specialized protein secretion systems, such as the Early Secretory Antigenic Target 6 secretion (ESX) system. Five ESX loci have been described in M. tuberculosis , called ESX-1 to ESX-5. The ESX-3 secretion system has been associated with mycobacterial metabolism and growth. The locus of this system is highly conserved across mycobacterial species. Metallo-proteins regulate negative ESX-3 transcription in high conditions of iron and zinc. Moreover, this secretion system is part of an antioxidant regulatory pathway linked to Zinc. EccA3, EccB3, EccC3, EccD3, and EccE3 are components of the ESX-3 secretion machinery, whereas EsxG-EsxH, PE5-PPE4, and PE15-PPE20 are proteins secreted by this system. In addition, EspG3 and MycP3 are complementary proteins involved in transport and proteolysis respectively. This system is associated to mycobacterial virulence by releasing the bacteria from the phagosome and inhibiting endomembrane damage response. Furthermore, components of this system inhibit the host immune response by reducing the recognition of M. tuberculosis -infected cells. The components of the ESX-3 secretion system play a role in drug resistance and cell wall integrity. Moreover, the expression data of this system indicated that external and internal factors affect ESX-3 locus expression. This review provides an overview of new findings on the ESX-3 secretion system, its regulation, expression, and functions. [Display omitted] • ESX3 system have a role in M. tuberculosis iron/zinc homeostasis and virulence. • ESX3 system is essential in M. tuberculosis survival in low iron conditions. • ESX3 gene cluster is regulated by iron, zinc and manganese. • ESX3 system inhibits host immune response. [ABSTRACT FROM AUTHOR]

Tuberculosis drug resistance (DR) is a global problem that is not fully elucidated. Previously, overexpression of esxG and esxH genes was reported in a multidrug-resistant (MDR) Mycobacterium tuberculosis isolate compared with a reference H37Rv strain. To evaluate the roles of esxG and esxH in DR, analysis of their regulatory and coding sequences in sensitive and resistant strains was performed, and the expression levels of their transcriptional regulators IdeR, Zur, and MntR were evaluated. esxG and esxH were expressed heterologously using mycobacterial constructs, and the orthologs Msmeg_0620 and Msmeg_0621 were attenuated in Mycobacterium smegmatis by antisense knockdown. We found no differences in the regulatory and coding sequences of esxG and esxH between the sensitive strain and the MDR isolate. Expression analysis of transcriptional regulators showed that ideR was upregulated in isoniazid (INH)-resistant isolates; in addition, growth inhibition of the M. smegmatis strain was observed in the presence of rifampicin (RIF) and INH when esxG and esxH were expressed heterologously, while faster growth in the presence of RIF was observed when the orthologs were attenuated. In conclusion, the expression of esxG and esxH altered the growth of Mycobacterium in the presence of INH and RIF, suggesting a potential association with DR. [ABSTRACT FROM AUTHOR]

Background: Mortality due to tuberculosis (TB) has increased due to the development of drug resistance, the mechanisms of which have not been fully elucidated. Our research group identified a low expression of lipF gene in Mycobacterium tuberculosis clinical isolates with drug resistance. The aim of this work was to evaluate the effect of lipase F (LipF) expression on mycobacterial drug resistance. Results: The effects of expressing lipF from Mycobacterium tuberculosis in Mycobacterium smegmatis on resistance to antituberculosis drugs were determined with resazurin microtiter assay plate and growth kinetics. Functionality of ectopic LipF was confirmed. LipF expression reduced the rifampicin (RIF) and streptomycin (STR) minimum inhibitory concentration (MIC) from 3.12 μg/mL to 1.6 μg/mL and 0.25 μg/mL to 0.06 μg/mL respectively, moreover a reduced M. smegmatis growth in presence of RIF and STR compared with that of a control strain without LipF expression (p < 0.05 and p < 0.01) was shown. Conclusions: LipF expression was associated with increased RIF and STR sensitivity in mycobacteria. Reduced LipF expression may contribute to the development of RIF and STR resistance in Mycobacterium species. Our findings provide information pertinent to understanding mycobacterial drug resistance mechanisms. [ABSTRACT FROM AUTHOR]

The smallest product of the Duchenne muscular dystrophy gene, dystrophin (Dp)71, is ubiquitously expressed in nonmuscle tissues. We previously showed that Dp71 expression in hepatic cells is modulated in part by stimulating factor 1 (Sp1), stimulating protein 3 (Sp3), and yin yang 1 (YY1) transcription factors, and that the polyaromatic hydrocarbon, β-naphthoflavone (β‑NF), downregulates Dp71 expression. The aim of the present study was to determine whether β‑NF represses Dp71 expression by altering mRNA stability or its promoter activity. Reverse transcription‑quantitative polymerase chain reaction was used to measure half‑life mRNA levels in β‑NF‑treated cells exposed to actinomycin D, an inhibitor of transcription, for 0, 4, 8, 12 and 16 h. Transient transfections with a plasmid carrying the Dp71 basal promoter fused to luciferase reporter gene were carried out in control and β‑NF‑treated cells. Electrophoretic mobility shift assays (EMSAs) were performed with labeled probes, corresponding to Dp71 promoter sequences, and nuclear extracts of control and β‑NF‑treated cells. To the best of our knowledge, the results demonstrated for the first time that this negative regulation takes place at the promoter level rather than the mRNA stability level. Interestingly, using EMSAs, β‑NF reduced binding of YY1, Sp1, and Sp3 to the Dp71 promoter. It also suggests that β‑NF may modulate the expression of other genes regulated by these transcription factors. In conclusion, β‑NF represses Dp71 expression in hepatic cells by altering binding of YY1, Sp1, and Sp3 to the Dp71 promoter. [ABSTRACT FROM AUTHOR]

Dystrophin Dp71, the smallest product encoded by the Duchenne muscular dystrophy gene, is ubiquitously expressed in all nonmuscle cells. Although Dp71 is involved in various cellular processes, the mechanisms underlying its expression have been little studied. In hepatic cells, Dp71 expression is down-regulated by the xenobiotic β-naphthoflavone. However, the effectors of this regulation remain unknown. In the present study we aimed at identifying DNA elements and transcription factors involved in Dp71 expression in hepatic cells. Relevant DNA elements on the Dp71 promoter were identified by comparing Dp71 5'-end flanking regions between species. The functionality of these elements was demonstrated by site-directed mutagenesis. Using EMSAs and ChIP, we showed that the Sp1 (specificity protein 1), Sp3 (specificity protein 3) and YY1 (Yin andYang 1) transcription factors bind to the Dp71 promoter region. Knockdown of Sp1, Sp3 and YY1 in hepatic cells increased endogenous Dp71 expression, but reduced Dp71 promoter activity. In summary, Dp71 expression in hepatic cells is carried out, in part, by YY1-, Sp1- and Sp3-mediated transcription from the Dp71 promoter. [ABSTRACT FROM AUTHOR]

Understanding drug resistance in Mycobacterium tuberculosis requires an integrated analysis of strain lineages, mutations and gene expression. Previously, we reported the differential expression of esxG, esxH, infA, groES, rpmI, rpsA and lipF genes in a sensitive M. tuberculosis strain and in a multidrug-resistant clinical isolate. Here, we have evaluated the expression of these genes in 24 clinical isolates that belong to different lineages and have different drug resistance profiles. In vitro, growth kinetics analysis showed no difference in the growth of the clinical isolates, and thus drug resistance occurred without a fitness cost. However, a quantitative reverse transcription PCR analysis of gene expression revealed high variability among the clinical isolates, including those with similar drug resistance profiles. Due to the complexity of gene regulation pathways and the wide diversity of M. tuberculosis lineages, the use of gene expression as a molecular signature for drug resistance is not straightforward. Therefore, we recommend that the expression of M. tuberculosis genes be performed individually, and baseline expression levels should be verified among several different clinical isolates, before any further applications of these findings. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is the most common form of liver cancer. The number of cases is increasing and the trend for the next few years is not encouraging. HCC is usually detected in the advanced stages of the disease, and pharmacological therapies are not entirely effective. For this reason, it is necessary to search for new therapeutic options. The objective of this work was to evaluate the effect of the drugs isotretinoin and thalidomide on c-MYC expression and cancer-related proteins in an HCC cellular model. The expression of c-MYC was measured using RT-qPCR and western blot assays. In addition, luciferase activity assays were performed for the c-MYC promoters P1 and P2 using recombinant plasmids. Dose-response-time analyses were performed for isotretinoin or thalidomide in cells transfected with the c-MYC promoters. Finally, a proteome profile analysis of cells exposed to these two drugs was performed and the results were validated by western blot. We demonstrated that in HepG2 cells, isotretinoin and thalidomide reduced c-MYC mRNA expression levels, but this decrease in expression was linked to the regulation of P1 and P1-P2 c-MYC promoter activity in isotretinoin only. Thalidomide did not exert any effect on c-MYC promoters. Also, isotretinoin and thalidomide were capable of inducing and repressing proteins associated with cancer. In conclusion, isotretinoin and thalidomide down-regulate c-MYC mRNA expression and this is partially due to P1 or P2 promoter activity, suggesting that these drugs could be promising options for modulating the expression of oncogenes and tumor suppressor genes in HCC. [ABSTRACT FROM AUTHOR]