Radio-miRs: a comprehensive view of radioresistance-related microRNAs.

Radiotherapy is a key treatment option for a wide variety of human tumors, employed either alone or alongside with other therapeutic interventions. Radiotherapy uses high-energy particles to destroy tumor cells, blocking their ability to divide and proliferate. The effectiveness of radiotherapy is due to genetic and epigenetic factors that determine how tumor cells respond to ionizing radiation. These factors contribute to the establishment of resistance to radiotherapy, which increases the risk of poor clinical prognosis of patients. Although the mechanisms by which tumor cells induce radioresistance are unclear, evidence points out several contributing factors including the overexpression of DNA repair systems, increased levels of reactive oxygen species, alterations in the tumor microenvironment, and enrichment of cancer stem cell populations. In this context, dysregulation of microRNAs or miRNAs, critical regulators of gene expression, may influence how tumors respond to radiation. There is increasing evidence that miRNAs may act as sensitizers or enhancers of radioresistance, regulating key processes such as the DNA damage response and the cell death signaling pathway. Furthermore, expression and activity of miRNAs have shown informative value in overcoming radiotherapy and long-term radiotoxicity, revealing their potential as biomarkers. In this review, we will discuss the molecular mechanisms associated with the response to radiotherapy and highlight the central role of miRNAs in regulating the molecular mechanisms responsible for cellular radioresistance. We will also review radio-miRs, radiotherapy-related miRNAs, either as sensitizers or enhancers of radioresistance that hold promise as biomarkers or pharmacological targets to sensitize radioresistant cells.

Effect of ascorbic acid and epidermal growth factor in a rat tibia defect.

PURPOSE: Bone repair aims to restore the anatomical, biomechanical, and functional integrity of the affected structure. Here we study the effects of ascorbic acid (AA) and epidermal growth factor (EGF) applied in a single dose and in combination on the repair of a noncritical bone defect model. METHODS: Twenty-four rats were divided into four groups: an intact G-1 control group, and three groups that underwent a noncritical bone defect in the right tibia: G-2 treated with AA, G-3 treated with EGF, and G-4 treated with AA in combination with EGF. After 21 days of treatment, rats were sacrificed, the tibias were dissected and a destructive biomechanical analysis of three-point flexion test was performed in a universal testing machine; the values of stiffness, resistance, maximum energy, and energy at maximum load were statistically compared. RESULTS: G-3 and G-4 recovered the biomechanical properties of strength and stiffness of an intact tibia 3 weeks after their application. Not so the energy and energy at maximum load. For G-2, only the stiffness of an intact tibia was recovered. CONCLUSIONS: EGF and AA-EGF applied to a noncritical bone defect in the rat tibia favors the recovery of bone resistance and stiffness.

Structural and Pharmacological Network Focused to miRNAs Involved in Rheumatoid Arthritis: A Systematic Review.

BACKGROUND: Rheumatoid Arthritis (RA) is a chronic autoimmune disease that has a prevalence of over one percent of the world population, causing substantial pain, joint deformity, and functional disability in patients. The identification and measurement of miRNAs are relatively easy to perform. Future studies will corroborate if miRNAs can fulfill their roles as biomarkers with either predictive or diagnostic evaluation of treatment potential and provide actual clinical utility. METHODS: In the last decade, various advances have been made regarding the identification of the origin and exact functions of miRNAs, allowing us to have a potential use both in the research and clinical fields. OBJECTIVE: This systematic review aimed to collect, analyze, and improve the current understanding of RA-related miRNAs and their applicability in therapeutics. A bibliographic search of the miRNAs involved in RA was carried out, and through the use of databases, their target genes and small molecules that had some relationship with their expression were searched. The analysis of these data was done through structural network analysis. RESULTS: During the network analysis, miR-30a, miR-30c, let-7a, miR-144, miR-17-5p, miR-124, miR -23b, miR-23, miR-15a, miR-16 were the most connected, which could be used as possible biomarkers or be candidates for further analysis due to their interaction with other miRNAs and genes. RESULTS: Additionally, this is the first systematic review, in which we proposed that small compounds like toxicants and drugs could have a potential role within RA because they regulate the expression of miRNAs involved in this pathology. Some of these compounds are commonly found as environmental contaminants, and others as drugs. These ideas open a new panorama of understanding RA, proposing possible causes or treatments against this pathology. Therefore, these small molecules would give us some indication of a relationship with RA, thereby helping in seeking causes, treatment, or prevention of this disease. CONCLUSION: This is the first time it is intended to use structural network analysis to determine possible biomarkers of AR for diagnosis and prognosis through the expression of these miRNAs and their relationship with compounds of daily life.

Effect of ascorbic acid and epidermal growth factor in a rat tibia defect

Purpose: Bone repair aims to restore the anatomical, biomechanical, and functional integrity of the affected structure. Here we study the effects of ascorbic acid (AA) and epidermal growth factor (EGF) applied in a single dose and in combination on the repair of a noncritical bone defect model. Methods: Twenty-four rats were divided into four groups: an intact G-1 control group, and three groups that underwent a noncritical bone defect in the right tibia: G-2 treated with AA, G-3 treated with EGF, and G-4 treated with AA in combination with EGF. After 21 days of treatment, rats were sacrificed, the tibias were dissected and a destructive biomechanical analysis of three-point flexion test was performed in a universal testing machine; the values of stiffness, resistance, maximum energy, and energy at maximum load were statistically compared. Results: G-3 and G-4 recovered the biomechanical properties of strength and stiffness of an intact tibia 3 weeks after their application. Not so the energy and energy at maximum load. For G-2, only the stiffness of an intact tibia was recovered. Conclusion: EGF and AA-EGF applied to a noncritical bone defect in the rat tibia favors the recovery of bone resistance and stiffness.

ACE and ACE2 Gene Variants Are Associated With Severe Outcomes of COVID-19 in Men.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the current coronavirus disease 2019 (COVID-19) pandemic, affecting more than 219 countries and causing the death of more than 5 million people worldwide. The genetic background represents a factor that predisposes the way the host responds to SARS-CoV-2 infection. In this sense, genetic variants of ACE and ACE2 could explain the observed interindividual variability to COVID-19 outcomes. In order to improve the understanding of how genetic variants of ACE and ACE2 are involved in the severity of COVID-19, we included a total of 481 individuals who showed clinical manifestations of COVID-19 and were diagnosed by reverse transcription PCR (RT-PCR). Genomic DNA was extracted from peripheral blood and saliva samples. ACE insertion/deletion polymorphism was evaluated by the high-resolution melting method; ACE single-nucleotide polymorphism (SNP) (rs4344) and ACE2 SNPs (rs2285666 and rs2074192) were genotyped using TaqMan probes. We assessed the association of ACE and ACE2 polymorphisms with disease severity using logistic regression analysis adjusted by age, sex, hypertension, type 2 diabetes, and obesity. The severity of the illness in our study population was divided as 31% mild, 26% severe, and 43% critical illness; additionally, 18% of individuals died, of whom 54% were male. Our results showed in the codominant model a contribution of ACE2 gene rs2285666 T/T genotype to critical outcome [odds ratio (OR) = 1.83; 95%CI = 1.01-3.29; p = 0.04] and to require oxygen supplementation (OR = 1.76; 95%CI = 1.01-3.04; p = 0.04), in addition to a strong association of the T allele of this variant to develop critical illness in male individuals (OR = 1.81; 95%CI = 1.10-2.98; p = 0.02). We suggest that the T allele of rs2285666 represents a risk factor for severe and critical outcomes of COVID-19, especially for men, regardless of age, hypertension, obesity, and type 2 diabetes.

The current role of NLRP3 inflammasome polymorphism in gout susceptibility.

INTRODUCTION: The NLR family pyrin domain containing 3 (NLRP3) signaling pathway has an important role in inflammation mediated by monosodium urate crystals in gout, and the characterization of single nucleotide polymorphisms (SNPs) have helped to recognize disease susceptibility. OBJECTIVE: The aim of this review is to provide an overview of the potential role of the inflammasome gene SNPs as a susceptibility factor for gout, discussing the current evidence available. METHODS: This review analyzes the relevant literature in the field of inflammasome SNPs and gout published in the last 10 years. The systematic research was performed in 16 articles, including both the SNPs associated and those not associated with gout, with the goal to have a complete overview. RESULTS: Sixty-nine SNPs from 10 different genes have been reported in the literature. Of these, 13 SNPs present association with gout susceptibility in different populations, while 56 have been established as not being associated with the disease. CONCLUSIONS: This review is a summary of the potential role of inflammasome gene SNPs and their association with gout risk, all of them related with NLRP3 inflammasome signaling, suggesting these polymorphisms are susceptibility candidates and genetic markers for gout. From the 69 SNPs analyzed in the literature, 13 of them have been associated with gout as follows: NLRP3 (rs3806268 and rs10754558), CARD8 (rs2043211), TLR4 (rs2149356), CD14 (rs2569190), IL-1ß (rs1143623), P2RX7 (rs2230911, rs1653624, rs7958316 and rs17525809) and PPARGC1B (rs45520937, rs10491360 and rs7712296) in different populations.

The feline calicivirus leader of the capsid protein causes survivin and XIAP downregulation and apoptosis.

Calicivirus infection causes intrinsic apoptosis, leading to viral propagation in the host. During murine norovirus infection, a reduction in the anti-apoptotic protein survivin has been documented. Here we report that in feline calicivirus infection, a downregulation of the anti-apoptotic proteins survivin and XIAP occur, which correlates with the translocation of the pro-apoptotic protein Smac/DIABLO from the mitochondria to the cytoplasm and the activation of caspase-3. Inhibition of survivin degradation by lactacystin treatment caused a delay in apoptosis progression, reducing virus release, without affecting virus production. However, the overexpression of survivin caused a negative effect in viral progeny production. Overexpression of the leader of the capsid protein (LC), but not of the protease-polymerase NS6/7, results in the downregulation of survivin and XIAP, caspase activation and mitochondrial damage. These results indicate that LC is responsible for the induction of apoptosis in transfected cells and most probably in FCV infection.

Varicella-Zoster Virus in Cerebrospinal Fluid at Relapses of Multiple Sclerosis is Infective in Vitro.

BACKGROUND: We have reported the presence of varicella-zoster virus (VZV) DNA and viral particles in the cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients during exacerbation. It is not known whether these viruses are infective. AIM: To determine whether the VZV found in CSF of MS patients in exacerbation phase are infective. METHODS: VZV found in CSF of MS patients was quantified by qPCR. Vero E6 cell cultures were incubated with CSF of five MS cases positive for VZV DNA, containing herpes-like viral particles. Propagated virus harvested from these cultures were used to infect new VeroE6 cells. Localization of an immediate-early and a late structural VZV proteins was monitored by confocal microscopy after 72 h. CSF from five non-inflammatory neurological (NIN) patients were used as controls. RESULTS: A cytopathic effect was found in cultured cells inoculated with CSF from MS patients. Both, structural VZV glycoprotein (gB) and immediate-early VZV protein (IE62) were detected in Vero E6 cultures inoculated with samples from all five MS cases. CSF from control patients produced no effect on Vero E6 cells. CONCLUSION: When present in the CSF at relapses of MS, VZV is infective under in vitro conditions.

Identification of Mycobacterium tuberculosis in the cerebrospinal fluid of patients with meningitis using nested PCR.

Tuberculous meningitis (TBM) is the most severe form of tuberculosis. It is caused by Mycobacterium tuberculosis (M. tuberculosis; MT) and it is very difficult to diagnose. The symptoms are similar to other infectious neurological diseases, such as neurocysticercosis, neuroborreliosis, or herpes viral infection. The aim of this study was to identify tuberculosis (TB) in cases of meningitis with clinical and laboratory evidence suggestive of TBM, and to confirm our findings with molecular tests for TB infection. We recruited patients with neurological symptoms who were examined at the neurology services of Hospitals of Instituto Mexicano del Seguro Social (IMSS) in Mexico City. A total of 144 consecutive patients with suggestive infectious meningitis were initially included; 94 cases of meningitis with clinical and laboratory evidence suggestive of TBM were included, but only 50 of these cases fulfilled the criteria for probable TBM. As the controls, we included 50 cases of meningitis with clinical and laboratory evidence suggestive of non-TBM. Cerebrospinal fluid (CSF) was collected from all 100 patients (cases and controls) and tested for TB by multiplex and nested PCR analyses. Nested PCR detected 0.1 fg of M. tuberculosis DNA. TB infection was confirmed with molecular tests in 49 patients from the 50 cases suggestive of TBM and in 1 of the 50 non-TBM cases. The analysis exhibited a sensitivity of 98.0%, a specificity of 92.0%, a positive predictive value of 88.0% and a negative predictive value of 98.0%. The use CSF for the analyses proved to be effective for the rapid diagnosis of TBM using a developed system of multiplex and nested PCR analyses in patients presenting neurological symptoms.

Crassulacean acid metabolism photosynthesis in columnar cactus seedlings during ontogeny: the effect of light on nocturnal acidity accumulation and chlorophyll fluorescence.

Columnar cacti have been traditionally classified as crassulacean acid metabolism (CAM) plants, though recent research indicates some cactus seedlings employ the C(3) pathway. To verify this last result, we measured acidity fluctuations for five columnar and one globular cactus species in seedlings from 1 to 48 d old after experimental exposure to 60% and 30% full sunlight, and in adult plants in the field. Using light-response curves of chlorophyll fluorescence, we determined photosynthetic efficiency (ΔF/Fm'), maximum electron transport rate (ETR(max)) and saturating photosynthetically active photon flux density (PPFD(sat)). All seedlings used the CAM pathway from their first day of development, and increases in nocturnal acidity depended on species, light treatment, and age. The CAM pathway was also found in adult plants. Cactus seedlings were able to acclimatize to light conditions by making photochemical adjustments, mainly by modifying the level of light at which photosystem II is saturated (PPFD(sat)). The presence of CAM in the seedlings of columnar cacti increases water-use efficiency and reduces the risk of photoinhibition. This could favor survival in the highly variable light levels characteristic of the desert environments of columnar cacti.