The Associations between Healthy Eating Patterns and Risk of Metabolic Dysfunction-Associated Steatotic Liver Disease: A Case-Control Study.

BACKGROUND: Although several epidemiological studies have identified an inverse association between healthy dietary patterns and metabolic dysfunction-associated steatotic liver disease (MASLD)/non-alcoholic fatty liver disease (NAFLD), little is known about the contribution of the food component to MASLD risk and the association between dietary patterns and severity of MASLD. This study aimed to investigate the association between healthy eating patterns and MASLD risk and severity of MASLD. METHODS: A case-control study including 228 patients diagnosed with MASLD and 228 controls was conducted. The modified Alternate Healthy Eating Index (AHEI), Dietary Approaches to Stop Hypertension (DASH) score, and Alternative Mediterranean Diet (AMED) score were evaluated based on information collected via a validated food-frequency questionnaire. MASLD was confirmed if participants presented with ultrasound-diagnosed fatty liver diseases along with at least one of five cardiometabolic risk factors and no other discernible cause. The logistic regression models were applied to estimate the odds ratio (OR) and 95% confidence interval (95% CI) of MASLD for dietary scores. RESULTS: Compared with participants in the lowest tertile, those in the highest tertile of AHEI had a 60% reduced risk of MASLD (OR: 0.40; 95% CI: 0.25-0.66). Similar associations were also observed for DASH and AMED, with ORs comparing extreme tertiles of 0.38 (95% CI: 0.22-0.66) and 0.46 (95% CI: 0.28-0.73), respectively. Further Stratified analysis revealed that the inverse associations between AHEI and DASH with MASLD risks were stronger among women than men, and the inverse associations between AMED and MASLD risks were more pronounced among participants with normal weight (OR: 0.22; 95% CI: 0.09-0.49). For components within the dietary score, every one-point increase in vegetable score and whole grain score within the AHEI was associated with an 11% (95% CI: 5-16%) and a 6% (95% CI: 0-12%) lower MASLD risk, respectively. Similar inverse associations with those scores were observed for the DASH and AMED. CONCLUSION: Greater adherence to healthy eating patterns was associated with reduced risk of MASLD, with vegetables and whole grains predominately contributing to these associations. These findings suggested that healthy eating patterns should be recommended for the prevention of MASLD.

An AhR-Caspase Axis Mediated Antiviral Apoptosis in an Arthropod.

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates immune modulation following exposure of animals to many environmental xenobiotics. However, its role in innate immune responses during viral infection is not fully understood, especially in invertebrates. In this study, a cDNA encoding an AhR homolog was cloned from an arthropod Litopenaeus vannamei (LvAhR). The expression of LvAhR was strongly upregulated in response to the challenge of white spot syndrome virus, a pathogen of highly contagious and fatal infectious disease of shrimp. The relevance of LvAhR to host defense was underlined by heightened susceptibility and elevated virus loads after AhR-silenced shrimp exposure to white spot syndrome virus. LvAhR could induce an apoptosis response through regulating the expression of L. vannamei caspase-1 (homologous to human caspase-3) by directly targeting its promoter that was required to couple with AhR nuclear translocator. Additionally, knockdown of L. vannamei caspase-1 resulted in elevated virus titers and a lower cell apoptotic rate. Thus, we demonstrate that an AhR-caspase axis restrains virus replication by promoting antiviral apoptosis, supporting a previously unidentified direct link between AhR signaling and caspase-mediated apoptosis signaling and, furthermore, suggests that the AhR-caspase axis could be a potential therapeutic target for enhancing antiviral responses in arthropods.

TNF-Receptor-Associated Factor 3 in Litopenaeus vannamei Restricts White Spot Syndrome Virus Infection Through the IRF-Vago Antiviral Pathway.

Tumor necrosis factor receptor (TNFR)-associated factors (TRAFs) are vital signaling adaptor proteins for the innate immune response and are involved in many important pathways, such as the NF-κB- and interferon regulatory factor (IRF)-activated signaling pathways. In this study, the TRAF3 ortholog from the shrimp Litopenaeus vannamei (LvTRAF3) was cloned and characterized. LvTRAF3 has a transcript of 3,865 bp, with an open reading frame (ORF) of 1,002 bp and encodes a polypeptide of 333 amino acids, including a conserved TRAF-C domain. The expression of LvTRAF3 in the intestine and hemocyte was up-regulated in response to poly (I:C) challenge and white spot syndrome virus (WSSV) infection. RNAi knockdown of LvTRAF3 in vivo significantly increased WSSV gene transcription, viral loads, and mortality in WSSV-infected shrimp. Next, we found that LvTRAF3 was not able to induce the activation of the NF-κB pathway, which was crucial for synthesis of antimicrobial peptides (AMPs), which mediate antiviral immunity. Specifically, in dual-luciferase reporter assays, LvTRAF3 could not activate several types of promoters with NF-κB binding sites, including those from WSSV genes (wsv069, wsv056, and wsv403), Drosophila AMPs or shrimp AMPs. Accordingly, the mRNA levels of shrimp AMPs did not significantly change when TRAF3 was knocked down during WSSV infection. Instead, we found that LvTRAF3 signaled through the IRF-Vago antiviral cascade. LvTRAF3 functioned upstream of LvIRF to regulate the expression of LvVago4 and LvVago5 during WSSV infection in vivo. Taken together, these data provide experimental evidence of the participation of LvTRAF3 in the host defense to WSSV through the activation of the IRF-Vago pathway but not the NF-κB pathway.

Penaeidins restrict white spot syndrome virus infection by antagonizing the envelope proteins to block viral entry.

Emerging studies have indicated that some penaeidins restrict virus infection; however, the mechanism(s) involved are poorly understood. In the present study, we uncovered that penaeidins are a novel family of antiviral effectors against white spot syndrome virus (WSSV), which antagonize the envelope proteins to block viral entry. We found that the expression levels of four identified penaeidins from Litopenaeus vannamei, including BigPEN, PEN2, PEN3, and PEN4, were significantly induced in hemocytes during the early stage of WSSV infection. Knockdown of each penaeidin in vivo via RNA interference resulted in elevated viral loads and rendered shrimp more susceptible to WSSV, while the survival rate was rescued via the injection of recombinant penaeidins. All penaeidins, except PEN4, were shown to interact with several envelope proteins of WSSV, and all four penaeidins were observed to be located on the outer surface of the WSSV virion. Co-incubation of each recombinant penaeidin with WSSV inhibited virion internalization into hemocytes. More importantly, we found that PEN2 competitively bound to the envelope protein VP24 to release it from polymeric immunoglobulin receptor (pIgR), the cellular receptor required for WSSV infection. Moreover, we also demonstrated that BigPEN was able to bind to VP28 of WSSV, which disrupted the interaction between VP28 and Rab7 - the Rab GTPase that contributes to viral entry by binding with VP28. Taken together, our results demonstrated that penaeidins interact with the envelope proteins of WSSV to block multiple viral infection processes, thereby protecting the host against WSSV.

RNAi screening identifies a new Toll from shrimp Litopenaeus vannamei that restricts WSSV infection through activating Dorsal to induce antimicrobial peptides.

The function of Toll pathway defense against bacterial infection has been well established in shrimp, however how this pathway responds to viral infection is still largely unknown. In this study, we report the Toll4-Dorsal-AMPs cascade restricts the white spot syndrome virus (WSSV) infection of shrimp. A total of nine Tolls from Litopenaeus vannamei namely Toll1-9 are identified, and RNAi screening in vivo reveals the Toll4 is important for shrimp to oppose WSSV infection. Knockdown of Toll4 results in elevated viral loads and renders shrimp more susceptible to WSSV. Furthermore, Toll4 could be a one of upstream pattern recognition receptor (PRR) to detect WSSV, and thereby leading to nuclear translocation and phosphorylation of Dorsal, the known NF-κB transcription factor of the canonical Toll pathway. More importantly, silencing of Toll4 and Dorsal contributes to impaired expression of a specific set of antimicrobial peptides (AMPs) such as anti-LPS-factor (ALF) and lysozyme (LYZ) family, which exert potent anti-WSSV activity. Two AMPs of ALF1 and LYZ1 as representatives are demonstrated to have the ability to interact with several WSSV structural proteins to inhibit viral infection. Taken together, we therefore identify that the Toll4-Dorsal pathway mediates strong resistance to WSSV infection by inducing some specific AMPs.