Biological Research最新文献

Purpose: The relationship between coronavirus disease 2019 (COVID-19) and rheumatoid arthritis (RA) remains uncertain. We aimed to assess the association between COVID-19 and RA through immune inflammation.

Methods: First, we conducted a meta-analysis on the risk of COVID-19 infection, hospitalization rate, and mortality rate for patients with RA. Then, Mendelian randomization (MR) was used to evaluate the causal relationship between COVID-19 and RA, and further analyzed the cytokines and immune cells in COVID-19 and RA. Finally, we obtained microarray datasets of COVID-19, RA patients, and normal controls from the GEO database. And performed functional, pathway enrichment, and immune cell infiltration analysis on differentially expressed genes between each group.

Results: The meta-analysis results suggested that the hospitalization rate and mortality rate of RA patients infected with COVID-19 were higher than those of the control population. MR analysis showed a positive correlation between COVID-19 infection and RA. We also found that interleukin 13 was associated with RA and COVID-19 infection. CD27 on IgD + CD24 + B cells and CD3 on CD39 + CD8 + T cells are common immune cell phenotypes in two diseases. In addition, COVID-19 function is enriched in immune responses mediated by leukocytes and neutrophils, while RA is significantly enriched in the proliferation of T and B lymphocytes. The results of immune cell infiltration showed that both diseases had more neutrophils and fewer CD8 T cells.

Conclusion: There are many similarities between COVID-19 and RA in immune inflammatory responses such as cytokines and immune cells. COVID-19 may lead to the development of RA through immune inflammation.

Background: Insect Ionotropic Receptors (IRs) are a relatively uncharted territory. Some studies have documented IR activation by recording neuronal activity in situ, others by their heterologous expression in Xenopus oocytes or mis-expressing IRs from Drosophila melanogaster or from the related D. sechellia into the D. melanogaster "ionotropic receptor decoder" neuron, which lacks the endogenous tuning receptor subunit but expresses IR-coreceptors.

Results: In this study, we first made use of Drosophila olfactory sensory neurons (OSNs) different from the "ionotropic receptor decoder", demonstrating that by replacing or introducing IRs alongside the native D. melanogaster ones, functional heteromeric complexes can be formed. IR41a1 from the lepidopteran Cydia pomonella exhibits binding to polyamines and the IR75d from the dipteran Drosophila suzukii binds hexanoic acid. Secondly, expressing D. suzukii's putative acid sensor IR64a into the "ionotropic receptor decoder" of D. melanogaster inhibits the response to the main activators of neighboring neurons from the same sensillum, despite that IR64a does not respond to acids. In situ hybridization on the antennae of D. suzukii unveils wide expression of IR64a in neurons proximal to the sacculus. Structural modeling analysis does not explain its absence of binding to acids; conversely, this approach identifies key amino acids features explaining the binding of hexanoic acid by IR75d. Finally, we have also explored alternative methods to heterologously express IRs based on Human Embryonic Kidney cells (HEK293). Despite observing correct expression of IRs in transfected cells through immunohistochemistry experiments, this approach did not achieve successful deorphanization of these receptors.

Conclusion: Our findings highlight the potential use of Drosophila OSNs as a valuable tool for functional characterization of IRs from different insect species: for the first time, we have provided evidence of IR-functionalities within alternative OSNs from the Drosophila's "ionotropic receptor decoder" neuron to functionally characterize and deorphanize IRs from lineages that are evolutionarily distant from the D. melanogaster subgroup, contributing to the understanding of chemosensory modalities in D. suzukii and C. pomonella, two globally significant agricultural pests. Additionally, the unsuccessful deorphanization in HEK cells highlights the complex requirements for IR functionality, supporting the use of Drosophila OSNs as a more suitable expression system.

Background: Carbapenemase-mediated resistance to carbapenems is a significant public health concern due to its potential for widespread dissemination. The KPC family of carbapenemases, encoded by the bla_KPC gene and often associated with Tn4401-like transposons, is particularly important for its ability to be transferred through diverse plasmid types. In Chile, KPC-producing Gram-negative bacteria have been detected in clinical settings; however, their occurrence in wastewater (WW) remains unknown. This study addresses this gap by characterizing carbapenem-resistant Enterobacterales isolates from a wastewater treatment plant (WWTP) in the Gran Concepción Metropolitan Area, Chile.

Results: This study identifies three carbapenem-resistant Enterobacterales isolates, namely Klebsiella pasteurii M2/A/C/34, Klebsiella pneumoniae subsp. pneumoniae M3/A/M/3, and Citrobacter freundii sensu stricto. M4/A/C/32, all exhibiting multidrug-resistant profiles and carrying the bla_KPC-2 gene encoding KPC-like carbapenemases. These isolates also possessed genes for extended-spectrum β-lactamases (ESBLs) and aminoglycoside-modifying enzymes (AMEs). Sequence typing revealed that M2/A/C/34, M3/A/M/3, and M4/A/C/32 belonged to novel sequence types, specifically ST470, ST273, and ST214, respectively. All isolates carried plasmids belonging to groups commonly associated with ARGs, including IncF, IncP, and IncA. Both Klebsiella isolates (M2/A/C/34 and M3/A/M/3) carried the class 1 integron (intl1) gene. Phylogenomic analysis reveals that M2/A/C/34 is related to strains from China and Pakistan, while M3/A/M/3 shares similarities with a strain from Germany, indicating their potential dissemination.

Conclusions: This study represents the first detection of carbapenem-resistant Enterobacterales carrying bla_KPC-2 in Chilean WW, including the novel identification of K. pasteurii. These findings emphasize the critical role of genomic surveillance in WW under the One Health framework, enabling the monitoring of carbapenemase-producing bacteria and associated ARGs. Sustained surveillance efforts are essential to comprehend the dynamics of antibiotic resistance in environmental reservoirs and to develop strategies for its containment and mitigation.

Stem cell technology plays a key role in advancing the understanding of neurological treatments and developing disease models that mimic human conditions. Differentiation of human bone marrow mesenchymal stem cells (hBMSCs) into neurons shows promise for treating neurodegenerative diseases. However, improving the functionality of these nerve cells remains a challenge. Graphene nanoplatelets (GNPs), with their excellent conductivity and biocompatibility, can enhance neuronal differentiation. This study examines the effect of GNPs on hBMSC differentiation. Cells cultured with varying GNP concentrations were assessed at 4 and 7 days using RT-qPCR and immunocytochemistry for neuronal markers MAP2, Nestin, and Tuj1. Results show that GNPs enhance marker expression and promote differentiation. Lower GNP concentrations maintained viability, while higher concentrations were detrimental. Morphological changes and increased fluorescence were observed with a 0.4 µg/ml GNP coating. Calcium imaging with Fluo4-AM indicated increased neuronal activity, underscoring GNPs' role in neuronal maturation. These findings suggest GNPs can drive stem cell differentiation toward neurons, offering new therapeutic potential for neurodegenerative diseases.

Background: Protein acetylation has emerged as essential for sperm function, attracting considerable attention recently. Acetylation, typically mediated by lysine acetyltransferases, involves attaching an acetyl group from acetyl-coenzyme A to lysine residues in proteins. Under alkaline conditions, however, acetylation can occur with minimal enzymatic involvement, primarily due to an elevated pH. As sperm migrate towards the ampulla, they experience increasing intracellular pH (pHi) while undergoing two crucial processes for fertilization: capacitation and the acrosome reaction (AR). Whereas the involvement of acetylating enzymes in these events has been partially investigated, the potential for non-enzymatic acetylation driven by the pHi alkalinization remains unknown.

Results: This study examined protein acetylation (acLys) levels in sperm incubated under capacitating conditions at pH 7.2 and pH 9.0, the latter condition potentially promoting non-enzymatic acetylation. To more precisely investigate the occurrence of non-enzymatic acetylation events, acetyltransferase activity was selectively attenuated using a specific cocktail of inhibitors. The functional implications of these conditions were assessed by examining key fertilization-related sperm attributes, including motility during capacitation and the ability to initiate the AR. Results demonstrated that alkaline conditions elevated basal acLys levels even with reduced acetyltransferase activity (P < 0.05), indicative of non-enzymatic acetylation. α-tubulin, particularly in the midpiece of the sperm flagellum, was identified as a specific target of this modification, correlating with diminished motility during capacitation. Following the AR, acLys levels in the head and midpiece decreased (P < 0.05) under conditions promoting non-enzymatic acetylation, accompanied by reductions in intracellular and acrosomal pH. In contrast, acLys levels and pH in the sperm head incubated under standard capacitating conditions (pH 7.2) remained stable. Sperm exposed to conditions conducive to non-enzymatic acetylation exhibited an impaired ability to trigger the AR (P < 0.05) compared to those maintained at pH 7.2. Notably, diminished acetylase activity emerged as a key factor impairing the maintenance of intracellular and acrosomal pH levels attained during capacitation, even under a pH of 9.0.

Conclusion: This study provides novel evidence for the occurrence of non-enzymatic acetylation in sperm, linked to the modulation of α-tubulin acetylation levels and motility during capacitation. Additionally, it suggests that acetyltransferase activity may play a crucial role in regulating intracellular and acrosomal pH levels in capacitated sperm, facilitating the AR.

Background: Lead is a ubiquitous environmental and industrial pollutant with worldwide health problems. Lead acetate toxicity induces both genotoxic effects and apoptosis. The present study aimed to investigate the usage of mesenchymal stem cells (MSCs) in the treatment of the genotoxic effect of lead acetate (LA) in the testis and its effect on the expression of the apoptosis marker caspase-3 and the proliferation marker Ki-67 in the injured testicular tissue.

Methods: Twenty-one adult male rats were used in this investigation (7 rats/group). Group I received saline and served as the control group (ctrl group); Group II received lead acetate (100 mg/kg) and was called the LA group; Group III received both lead acetate (100 mg/kg) and MSCs (1 × 10⁶ cells/rat) and was called the LA-MSCs group. Body and testis weight, plus semen analysis, were performed in all groups. Reproductive hormones, serotonin, and cortisol were determined in sera. Additionally, oxidative/antioxidative status and lead acetate-induced genetic variations were investigated. Immunohistochemical staining for the proliferation marker Ki-67 and the apoptosis marker caspase-3 was also performed.

Results: revealed that the weight of the body and testis and semen parameters (sperm count, viability, and motility) of the LA group exhibited significant reduction compared to the Ctrl and the LA-MSCs group. In addition, the LA group showed reproductive hormonal imbalance and an increase in oxidative stress biomarkers compared to the LA-MSCs group that showed a significant improvement in these parameters. Compared to the ctrl group, the LA group showed a highly genetic distance value (0.0031), while the LA-MSCs group showed a low genetic distance value (0.0019). This illustrated that the LA-MSCs group exhibited reduced genetic variation induced by LA compared to the LA group. Histological evaluation indicated the presence of severe diffuse degeneration and necrosis in the spermatocytes in the LA group compared to the control one, while co-treatment by MSCs induced significant reduction in these degenerative changes. Immunohistochemical investigation revealed increased expression of the caspase-3 antibody in the testicular tissue of the LA group, while it is significantly decreased in the LA- MSCs group. In contrast, the KI67 antibody revealed a significant decrease in its expression in the LA group, while it was significantly increased in the LA-MSCs group after treatment by MSCs.

Conclusions: It can be concluded that the MSCs are a potential therapeutic for the treatment of testicular dysfunction induced by LA through the reduction of oxidative stress, genotoxic effect, and apoptosis marker caspase-3, and an increase in the proliferation marker Ki-67 in the testicular tissue associated with restoration of hormonal imbalance.

Background: A splice mutation that causes skipping of exon 17 in the KIT gene is a major reason for the dominant white phenotype of pigs. Exon 17 of the KIT gene may be related to differences in testis size and sperm quality among different pig breeds. Investigating the effects of exon 17 of the KIT gene on spermatogonia differentiation and testicular development is essential for understanding the genetic causes of reduced fertility and semen quality in pigs. To better understand the effects of the splice mutation of KIT on porcine spermatogenesis, we described an exon 17 deletion mouse model (Kit ^D17/+) constructed by simulating splice mutations in KIT for functional verification.

Results: Deletion of exon 17 of Kit severely impaired the differentiation of spermatogonia and promoted the apoptosis of germ cells, resulting in testicular dysplasia and decreased sperm quality and male fertility. Further transcriptomic analysis revealed inhibited expression of genes involved in meiosis and spermatogenesis and attenuated MAPK-ERK signaling in the testicular tissues of Kit ^D17/+ mice. The attenuated MAPK-ERK signaling caused by impaired Kit phosphorylation was confirmed by western blotting.

Conclusions: Our study demonstrated that deletion of exon 17 of Kit severely impaired spermatogenesis and testicular development, leading to decreased semen quality and male fertility. These findings verified the function of exon 17 in the Kit gene and provide a theoretical basis for improving the semen quality of dominant white pigs through correction of the splice mutation of KIT.