Vitamin B6 ameliorates acute pancreatitis by suppressing the caspase3 signaling pathway.

BACKGROUND: Acute pancreatitis (AP) is a prevalent exocrine inflammatory disorder of the pancreas characterized by pancreatic inflammation and injury to acinar cells. Vitamin B6 (VB6) is a vital nutrient that plays a significant role in preserving human health and has anti-inflammatory and anti-apoptotic effects. METHODS: This study aimed to explore the potential pancreatic protective effects of VB6 in mitigating pancreatic inflammation and apoptosis induced by taurocholate sodium (TLCS) in an AP model and to assess the underlying mechanism of action. AP was induced in Sprague‒Dawley (SD) rats through TLCS administration and lipopolysaccharide (LPS)-treated AR42J cells, followed by treatment with VB6. RESULTS: Various parameters associated with AP were assessed in both plasma and pancreatic tissues. VB6 has been shown to ameliorate the severity of AP through various mechanisms. It effectively reduces the levels of serum amylase, lipase, and inflammatory factors, thereby mitigating histological injury to the pancreas. Moreover, VB6 inhibited pancreatic apoptosis by downregulating bax expression and up-regulating Bcl2 expression in TLCS-treated rats. Additionally, VB6 suppressed the expression of caspase3. The anti-inflammatory and anti-apoptotic effects of VB6 observed in LPS-treated AR42J cells are consistent with those observed in a rat model of AP. CONCLUSIONS: These results suggest that VB6 exerts anti-inflammatory and anti-apoptotic effects through inhibition of the caspase3 signaling pathway and has a protective effect against AP.

A genome-wide CRISPR screen identified host genes essential for intracellular Brucella survival.

Brucella is a zoonotic intracellular bacterium that poses threats to human health and economic security. Intracellular infection is a hallmark of the agent Brucella and a primary cause of distress, through which the bacterium regulates the host intracellular environment to promote its own colonization and replication, evading host immunity and pharmaceutical killing. Current studies of Brucella intracellular processes are typically premised on bacterial phenotype such as intracellular bacterial survival, followed by biochemical or molecular biological approaches to reveal detailed mechanisms. While such processes can deepen the understanding of Brucella-host interaction, the insights into host alterations in infection would be easily restricted to known pathways. In the current study, we applied CRISPR Cas9 screen to identify host genes that are most affected by Brucella infection on cell viability at the genomic level. As a result of CRISPR screening, we firstly identified that knockout of the negatively selected genes GOLGA6L6, DEFB103B, OR4F29, and ERCC6 attenuate the viability of both the host cells and intracellular Brucella, suggesting these genes to be potential therapeutic targets for Brucella control. In particular, knockout of DEFB103B diminished Brucella intracellular survival by altering host cell autophagy. Conversely, knockout of positive screening genes promoted intracellular proliferation of Brucella. In summary, we screened host genes at the genomic level throughout Brucella infection, identified host genes that are previously not recognized to be involved in Brucella infection, and provided targets for intracellular infection control.IMPORTANCEBrucella is a Gram-negative bacterium that infects common mammals causing arthritis, myalgia, neuritis, orchitis, or miscarriage and is difficult to cure with antibiotics due to its intracellular parasitism. Therefore, unraveling the mechanism of Brucella-host interactions will help controlling Brucella infections. CRISPR-Cas9 is a gene editing technology that directs knockout of individual target genes by guided RNA, from which genome-wide gene-knockout cell libraries can be constructed. Upon infection with Brucella, the cell library would show differences in viability as a result of the knockout and specific genes could be revealed by genomic DNA sequencing. As a result, genes affecting cell viability during Brucella infection were identified. Further testing of gene function may reveal the mechanisms of Brucella-host interactions, thereby contributing to clinical therapy.

A Phi29-based unbiased exponential amplification and genotyping approach improves pathogen detection in tick samples.

Ticks are vectors for many infectious diseases, such as spotted fever group (SFG) rickettsioses and borreliosis, and are valuable in the study of pathogen ecology. Ticks have several growth stages that vary considerably in size; therefore, in most cases, DNA extracted from ticks is insufficient for subsequent studies, particularly for multiple pathogen screening and genotyping. Unbiased amplification of DNA from tick samples before analysis is a major requirement for subsequent ecological surveys and other studies. Phi29 DNA polymerase, an enzyme that exhibits strand displacement activity, can exponentially amplify DNA randomly, generating large quantities of DNA. In the present study, we developed a Phi29-based unbiased exponential amplification (PEA) assay to obtain sufficient tick DNA for genetic analysis. By using tick-borne pathogen detection and genotyping as a model, we tested and evaluated the feasibility of the assay. DNA was extracted from single ticks and subjected to PEA. The results showed that tick DNA could be amplified up to 105 fold. The amplified products were successfully used for pathogen screening and genotyping. Rickettsia was successfully detected and genotyped in samples with amplified DNA from single ticks. Furthermore, we identified a new genotype of Rickettsia from ticks collected from Dandong city, Liaoning province, Northeast China. This PEA assay is universal and can be extended to other applications where the quantity of DNA is greatly limited.

High Incidence of a Novel Rickettsia Genotype in Parasitic Haemaphysalis longicornis from China-North Korea Border.

Ticks are notorious vectors for various pathogens that cause infections in animals and humans worldwide. Rickettsia spp., a zoonotic tick-borne pathogen that could be used as a weapon agent, is widely spread in China. In the present study, ticks were collected for species identification and Rickettsia screening. PCR amplification targeting the tick 18s rRNA gene was first conducted for species validation, and then, amplification was conducted for the Rickettsia housekeeping gene for the infection rate and phylogenetic analysis. The collected ticks were identified as Haemaphysalis longicornis, 7.36% of which were Rickettsia-positive. The phylogenetic analysis showed that the Rickettsia in the parasitic ticks belonged to a novel genotype, whose closest genetic relationship was with Rickettsia heilongjiangenesis. The samples were collected in Dandong, a city on the border between China and North Korea. Considering the geographical and biological situations of the sampling sites, more extensive surveillance and risk evaluation of the tick species and tick-borne diseases are required.

Association between glucose-regulated protein and neutrophil apoptosis in severe acute pancreatitis.

OBJECTIVE: This study aimed to investigate the role of glucose regulated protein 78 (GRP-78) in the apoptosis of neutrophils in rats with severe acute pancreatitis. METHODS: A total of 54 SD male rats were randomly assigned into 2 groups: sham group (n=24) and pancreatitis group (n=30). Severe acute pancreatitis was induced by retrograde cholangiopancreatography injection of sodium taurocholate. Rats were sacrified at 3 h, 6 h and 12 h after injection. In control group, rats received laparotomy, but the pancreates remained intact. The serum amylase was detected at different time points, and flow cytometry was done to detect the apoptosis of neutrophils. Proteins were extracted from neutrophils and subjected to detection of GRP78 and Mcl-1 expression by Western blot assay. HE staining was performed for pathological scoring of the pancreas. RESULTS: The serum amylase in pancreatitis group increased markedly when compared with control group (P<0.01). In SAP group, the serum amylase increased gradually over time (P<0.01). HE staining showed a lot of inflammatory cells and infiltration of red blood cells and the apoptosis rate of neutrophils reduced gradually (P<0.01). Western blot assay showed the protein expression of GRP-78 and Mcl-1 increased in neutrophils over time. CONCLUSION: In rats with SAP, the apoptosis rate of neutrophils reduced over time, which may be associated to the stress induced expression of GRP78 and subsequent activation of Mcl-1 resulting in suppression of neutrphil apoptosis over time.