Methionine Restriction Prevents Lipopolysaccharide-Induced Acute Lung Injury via Modulating CSE/H2S Pathway

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) result in high mortality, whereas effective treatments are limited. Methionine restriction (MR) has been reported to offer various benefits against multiple pathological processes of organ injuries. However, it remains unknown whether MR has any potential therapeutic value for ALI/ARDS. The current study was set to investigate the therapeutic potential of MR on lipopolysaccharide (LPS)-induced ALI and its underlying mechanisms. We found that MR attenuated LPS-induced pulmonary edema, hemorrhage, atelectasis, and alveolar epithelial cell injuries in mice. MR upregulated cystathionine-gamma-lyase (CSE) expression and enhanced the production of hydrogen sulfide (H2S). MR also inhibited the activation of Toll-like receptors 4 (TLR4)/NF-κB/NOD-like receptor protein 3 (NLRP3), then reduced IL-1β, IL-6, and TNF-α release and immune cell infiltration. Moreover, the protective effects of MR on LPS-induced ALI were abrogated by inhibiting CSE, whereas exogenous H2S treatment alone mimicked the protective effects of MR in Cse−/− mice after LPS administration. In conclusion, our findings showed that MR attenuated LPS-induced lung injury through CSE and H2S modulation. This work suggests that developing MR towards clinical use for ALI/ARDS patients may be a valuable strategy.

N6-Methyladenosine Modification Changes in the Genome of Paulownia Fortunei Seedlings Infected With Phytoplasma

Background: Phytoplasmas induce diseases in more than 1,000 plant species and cause substantial ecological damage and economic losses, but the specific pathogenesis of phytoplasma has not yet been clarified. N6-methyladenosine sequencing (m6A-seq) has been applied mainly to model plants and not to woody plants. Results: In this study, we applied m6A-seq to study changes in m6A modification in the Paulownia fortunei genome after phytoplasma infection. We found that the m6A modification level in seedlings infected with the phytoplasma that causes Paulownia witches' broom (PaWB) was slightly higher than the m6A modification level in PaWB-infected seedlings treated with 60 mg·L−1 methyl methanesulfonate (MMS). MMS has been shown to restore PaWB-infected seedlings to their normal form and no phytoplasma can be detected in MMS-treated PaWB-infected seedlings. RNA sequencing (RNA-seq) and m6A-seq were used to analyze the expression of genes with m6A peaks and m6A motifs in genes, respectively. The correlation analysis between the RNA-seq and m6A-seq data detected that a total of 315 differentially methylated genes were predicted to be significantly differentially expressed at the transcriptome level. The functions of genes related to PaWB were predicted by functional enrichment analysis, and two genes related to maintenance of the basic mechanism of stem cells in shoot apical meristem were discovered. One of the genes encodes the receptor protein kinase CLV2 (Paulownia_LG2G000076), and the other gene encodes the homeobox transcription factor STM (Paulownia_LG15G000976). The m6A modification levels were higher in PaWB-infected seedlings than they were in MMS-treated seedlings. In addition, genes F-box (Paulownia_LG17G000760) and MSH5 (Paulownia_LG8G001160) had exon skipping and mutually exclusive exon types of alternative splicing in PaWB-infected seedling treated with MMS. RT-PCR verified that the alternative splicing of these two genes was related to m6A modification. Conclusions: In this study, we applied m6A-seq to determine methylation levels in phytoplasma-infected Paulownia, and combined m6A-seq with transcriptome analysis to screen differentially expressed genes associated with PaWB. Also analyzed the effect of m6A methylation on alternative splicing. In future studies, we plan to verify genes directly related to PaWB and methylation-related enzymes in Paulownia to elucidate the pathogenicity mechanism of PaWB caused by phytoplasma invasion.

GABA receptors in the olfactory epithelium of the gilthead seabream (Sparus aurata)

Exposure to high PCO2/low pH seawater induces behavioural alterations in fish; a possible explanation for this is a reversal of Cl−/HCO3− currents through GABAA receptors (the GABAA receptor theory). However, the main evidence for this is that gabazine, a GABAA receptor antagonist, reverses these effects when applied to the water, assuming that exposure to systems other than the CNS would be without effect. Here, we show the expression of both metabotropic and ionotropic GABA receptors, and the presence of GABAA receptor protein, in the olfactory epithelium (OE) of gilthead seabream. Furthermore, exposure of the OE to muscimol (a specific GABAA receptor agonist) increases or decreases the apparent olfactory sensitivity to some odorants. Thus, although the exact function of GABAA receptors in the OE is not yet clear, this may complicate the interpretation of studies wherein water-borne gabazine is used to reverse the effects of high CO2 levels on olfactory-driven behaviour in fish.

Electroacupuncture Prevents the Depression-Like Behavior by Inhibiting the NF-κB/NLRP3 Inflammatory Pathway in Hippocampus of Mice Subjected to Chronic Mild Stress

<b><i>Background:</i></b> The precise physiological mechanisms of acupuncture in the treatment of depression are still unknown. This study aimed to observe the effects of electroacupuncture (EA) on depression-like behavior of mouse in chronic mild stress (CMS) model and explore the underlying mechanism. <b><i>Methods:</i></b> The depression model was established by using CMS method for 6 weeks. After the third week of the CMS paradigm, EA treatment was performed daily for 15 min over a period of 3 weeks. The antidepressant-like effects of EA were evaluated using the sucrose preference test and the forced swimming test (FST). The protein levels of the nuclear factor-kappa B (NF-κB), p-NF-κB, inhibitor of NF-κB, p-IκBα, NOD-like receptor protein 3, interleukin (IL)-6, IL-1β, IL-18, and tumor necrosis factor-α (TNF-α) in hippocampus of mice were detected. <b><i>Results:</i></b> Sucrose preference was decreased after 6 weeks of CMS and the effects of CMS was reversed by EA. CMS increased immobility time and decreased latency to the first immobility in the FST test, but these effects were reversed by EA. CMS-induced nuclear entry of NF-κB (nuclear/cytoplasmic ratio of NF-κB) with an increase in protein levels of p-NF-κB and p-IκBα in the hippocampus. The CMS also increased NLRP3 levels in the hippocampus. However, these effects were reversed by EA. In addition, the levels of IL-6, IL-1β, IL-18, and TNF-α in the hippocampus were increased by CMS, and these effects of stress were reversed by EA. <b><i>Conclusion:</i></b> EA prevented CMS-induced depressive-like behaviors by inhibiting NF-κB/NLRP3 inflammatory pathway.

Resolving Protein Conformational Plasticity and Substrate Binding Through the Lens of Machine-Learning

A long-standing target in elucidating the biomolecular recognition process is the identification of binding-competent conformations of the receptor protein. However, protein conformational plasticity and the stochastic nature of the recognition processes often preclude the assignment of a specific protein conformation to an individual ligand-bound pose. In particular, we consider multi-microsecond long Molecular dynamics simulation trajectories of ligand recognition process in solvent-inaccessible cavity of two archtypal systems: L99A mutant of T4 Lysozyme and Cytochrome P450. We first show that if the substrate-recognition occurs via long-lived intermediate, the protein conformations can be automatically classified into substrate-bound and unbound state through an unsupervised dimensionality reduction technique. On the contrary, if the recognition process is mediated by selection of transient protein conformation by the ligand, a clear correspondence between protein conformation and binding-competent macrostates can only be established via a combination of supervised machine learning (ML) and unsupervised dimension reduction approach. In such scenario, we demonstrate that a priori random forest based supervised classification of the simulated trajectories recognition process would help characterize key amino-acid residue-pairs of the protein that are deemed sensitive for ligand binding. A subsequent unsupervised dimensional reduction via time-lagged independent component analysis of the selected residue-pairs would delineate a conformational landscape of protein which is able to demarcate ligand-bound pose from the unbound ones. As a key breakthrough, the ML-based protocol would identify distal protein locations which would be allosterically important for ligand binding and characterise their roles in recognition pathways.

Connexin 43: A Target for the Treatment of Inflammation in Secondary Complications of the Kidney and Eye in Diabetes

Of increasing prevalence, diabetes is characterised by elevated blood glucose and chronic inflammation that precedes the onset of multiple secondary complications, including those of the kidney and the eye. As the leading cause of end stage renal disease and blindness in the working population, more than ever is there a demand to develop clinical interventions which can both delay and prevent disease progression. Connexins are membrane bound proteins that can form pores (hemichannels) in the cell membrane. Gated by cellular stress and injury, they open under pathophysiological conditions and in doing so release ‘danger signals’ including adenosine triphosphate into the extracellular environment. Linked to sterile inflammation via activation of the nod-like receptor protein 3 inflammasome, targeting aberrant hemichannel activity and the release of these danger signals has met with favourable outcomes in multiple models of disease, including secondary complications of diabetes. In this review, we provide a comprehensive update on those studies which document a role for aberrant connexin hemichannel activity in the pathogenesis of both diabetic eye and kidney disease, ahead of evaluating the efficacy of blocking connexin-43 specific hemichannels in these target tissues on tissue health and function.

Sex Differences in Animal Models of Sodium-Valproate-Induced Autism in Postnatal BALB/c Mice: Whole-Brain Histoarchitecture and 5-HT2A Receptor Biomarker Evidence

Autism spectrum disorder (ASD) is characterised by problems with social interaction, verbal and nonverbal communication and repetitive behaviour. In mice, the 14th postnatal day is believed to correspond to the third trimester of human embryonic development and is considered a vital period for central nervous system development. It has been shown that ASD affects 2 to 3 times more male than female individuals. In the present study, ASD was induced in 14 postnatal day (PND) BALB/c mice using valproic acid (VPA). VPA administration brought about substantial differences in the histoarchitecture of the brain in both male and female mice, linked to behavioural deficits. We observed that both male and female mice showed similar morphological changes in the prefrontal cortex, hippocampus and Purkinje cells. We also observed hair loss from PND 17 to 25, which was again similar between male and female mice. However, there were higher rates of change in the cerebral cortex, frontal cortex and temporal lobe and hippocampus in VPA-treated male animals. With respect to the cerebellum, we did not observe any alterations by haematoxylin and eosin (H&E) staining, but detailed morphological observation using scanning electron microscopy (SEM) showed a higher rate of phenotype changes in VPA-treated male animals. Moreover, 5-HT2A receptor protein levels were upregulated in the cerebral cortex, hippocampus and Purkinje cells in VPA-treated male mice compared with control animals and VPA-treated female mice, as shown by immunohistochemical analysis. Based on all these findings, we conclude that male animals are more susceptible to VPA-induced ASD than females.

The Effects of Pulsed Electric Field On The Interaction Between SARS-Cov-2 And Human ACE2: Y505 Is A Key Target

A novel coronavirus has rapidly spread to almost every country in the world, causing over 233 million confirmed cases of coronavirus disease 2019 (COVID-19) and over 209,761,242 deaths by late September 2021. Binding the receptor binding domain (RBD) to the host cell surface receptor protein, angiotensin converter enzyme (ACE2), is a key step in virus infection. In this study, we applied a pulsed electric field to the RBD/ACE2 complex based on molecular dynamics simulation and demonstrated that the electric field affects the structure and binding affinity of the complex. Additionally, residue Y505 is the crucial medium for the effects of electric field on the complex. Overall, these results may help apply an external electric field to virus suppression.

MicroRNA-223 Downregulation Promotes HBx-Induced Podocyte Pyroptosis by Targeting the NLRP3 Inflammasome

Hepatitis B virus (HBV) and its related protein, HBV X (HBx), play an important role in podocyte injury in HBV-associated glomerulonephritis (HBV-GN). MiR-223 is expressed in several diseases, including HBV-associated disease, while nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome plays a major role in pyroptosis. This study aims to determine the potential function and related mechanism of miR-223 in HBx-induced podocyte pyroptosis. We observed that the results of polymerase chain reaction indicated that miR-223 was downregulated in HBx-transfected podocytes. Transfection of miR-223 mimic eliminated the expression of NLRP3 inflammasome and its related cytokines released by NLRP3 overexpression. Moreover, the transfection of HBx and NLRP3-overexpressing plasmids increased the expression of pyroptosis-related proteins especially in the presence of miR-223 inhibitors. In conclusion, miR-223 downregulation plays an important role in HBx-induced podocyte pyroptosis by targeting the NLRP3 inflammasome, suggesting that miR-223 is a potential therapeutic target for alleviating HBV-GN inflammation.

Recent advances in the discovery of protein tyrosine phosphatase SHP2 inhibitors

Src homology 2 domain-containing protein tyrosine phosphatase (SHP2) is a non-receptor protein tyrosine phosphatase encoded by the Ptpn11 gene, which regulates cell growth, differentiation and apoptosis via modulating various signaling...