Fine particulate matter (PM_2.5) is often linked to a range of respiratory diseases and cellular damage. Although studies have shown that the expression profiles of microRNAs (miRNAs) are altered during lung damage brought on by PM_2.5, the underlying functions of miRNAs remain poorly understood. In this research, we explored the role of PM_2.5-induced apoptosis in detail and focused on the miRNA (miR-212-5p) that regulates apoptosis. Through a dual-luciferase assay, a direct targeting connection between laminin subunits γ2 (LAMC2) and α3 (LAMA3) and miR-212-5p was successfully demonstrated. This study focused on revealing the negative regulatory relationship between miR-212-5p and LAMC2 and LAMA3, providing important clues for a deeper understanding of the relevant physiological and pathological mechanisms. The present study showed that LAMC2 and LAMA3 positively regulate the PI3K-AKT pathway and negatively regulate the NF-κB pathway, which directly leads to significant changes in apoptosis rates. This study reveals a previously unrecognized molecular mechanism by showing that miR-212-5p directly targets LAMC2 and LAMA3 and thus associates with PM_2.5-induced apoptosis via the PI3K/AKT/NF-κB pathway. These findings not only redefine the role of miR-212-5p in apoptosis but also open up new avenues for future research.

In aquaculture, viral diseases pose a significant threat and can lead to substantial economic losses. The primary defense against viral invasion is the innate immune system, with interferons (IFNs) playing a crucial role in mediating the immune response. With advancements in molecular biology, the role of non-coding RNA (ncRNA), particularly microRNAs (miRNAs), in gene expression has gained increasing attention. While the function of miRNAs in regulating the host immune response has been extensively studied, research on their immunomodulatory effects in teleost fish, including silver carp (Hyphthalmichthys molitrix), is limited. Therefore, this research aimed to investigate the immunomodulatory role of microRNA-30b-5p (miR-30b-5p) in the antiviral immune response of silver carp (Hypophthalmichthys molitrix) by targeting cytokine receptor family B5 (CRFB5) via the JAK/STAT signaling pathway. In this study, silver carp were stimulated with polyinosinic-polycytidylic acid (poly (I:C)), resulting in the identification of an up-regulated miRNA (miR-30b-5p). Through a dual luciferase assay, it was demonstrated that CRFB5, a receptor shared by fish type I interferon, is a novel target of miR-30b-5p. Furthermore, it was found that miR-30b-5p can suppress post-transcriptional CRFB5 expression. Importantly, this study revealed for the first time that miR-30b-5p negatively regulates the JAK/STAT signaling pathway, thereby mediating the antiviral immune response in silver carp by targeting CRFB5 and maintaining immune system stability. These findings not only contribute to the understanding of how miRNAs act as negative feedback regulators in teleost fish antiviral immunity but also suggest their potential therapeutic measures to prevent an excessive immune response.

The ubiquitous Gram-negative bacterial pathogen Aeromonas veronii (A. veronii) can easily cause inflammatory reactions in aquatic organisms, resulting in high mortality and huge economic losses. MicroRNAs (miRNAs) participate in immune regulation and have certain conserved properties. MiRNAs are involved in the immune responses of a variety of teleost fish infected with bacteria, whereas there is no related report in silver carp (Hypophthalmichthys molitrix). Therefore, we identified the expression profiles of miRNA in silver carp stimulated by A. veronii and LPS. Among them, the quantity of differentially expressed miRNAs (DEmiRNAs) obtained in the silver carp challenge group was 73 (A. veronii) and 90 (LPS). The GO enrichment and analysis of KEGG pathways have shown that the predicted target genes are mainly associated with lipid metabolism and the immune response in silver carp. This indicates the possibility that miRNAs play a role in regulating immune-related pathways. In addition, a total of eight DEmiRNAs validated the accuracy of the sequencing result via quantitative real-time PCR (qRT-PCR). Finally, we selected the silver carp head kidney macrophage cells (HKCs) as model cells and proved that miR-30b-5p can regulate the inflammatory response in silver carp HKCs. This study lays the foundation for exploring miRNA regulation in silver carp during pathogenic bacterial infection. In addition, it provides a reference for the future development of non-coding RNA antibacterial drugs.

Swine wastewater (SW) has a high chemical oxygen demand (COD) content and is difficult to degrade; an effective strategy to address this issue is through biodegradation, which poses negligible secondary pollution risks and ensures cost-efficiency. The objectives of this study were to isolate an effective COD-degrading strain of SW, characterize (at the molecular level) its transformation of SW, and apply it to practical production. A strain of Corynebacterium xerosis H1 was isolated and had a 27.93% ± 0.68% (mean ± SD) degradation rate of COD in SW. This strain precipitated growth in liquids, which has the advantage of not needing to be immobilized, unlike other wastewater-degrading bacteria. Based on analysis by Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), this bacterium removed nitrogen-containing compounds in SW, with proteins and lipids decreasing from 41 to 10% and lignins increasing from 51 to 82%. Furthermore, the enhancement of the sequencing batch reactor (SBR) with strain H1 improved COD removal in effluent, with reductions in the fluorescence intensity of aromatic protein I, aromatic protein II, humic-like acids, and fulvic acid regions. In addition, based on 16S rRNA gene sequencing analysis, SBR_H1 successfully colonized some H1 bacteria and had a higher abundance of functional microbiota than SBR_C. This study confirms that Corynebacterium xerosis H1, as a carrier-free efficient strain, can be directly applied to swine wastewater treatment, reducing carrier costs and the risk of secondary pollution. The discovery of this strain enriches the microbial resource pool for SW COD degradation and provides a new scheme with both economic and environmental friendliness for large-scale treatment.

MicroRNAs (miRNAs) are highly conserved endogenous single-stranded non-coding RNA molecules that play a crucial role in regulating gene expression to maintain normal physiological functions in fish. Nevertheless, the specific physiological role of miRNAs in lower vertebrates, particularly in comparison to mammals, remains elusive. Additionally, the mechanisms underlying the control of antiviral responses triggered by viral stimulation in fish are still not fully understood. In this study, we investigated the regulatory impact of miR-1388 on the signaling pathway mediated by IFN regulatory factor 3 (IRF3). Our findings revealed that following stimulation with the viral analog poly(I:C), the expression of miR-1388 was significantly upregulated in primary immune tissues and macrophages. Through a dual luciferase reporter assay, we corroborated a direct targeting relationship between miR-1388 and tumor necrosis factor receptor (TNFR)-associated factor 3 (TRAF3). Furthermore, our study demonstrated a distinct negative post-transcriptional correlation between miR-1388 and TRAF3. We observed a significant negative post-transcriptional regulatory association between miR-1388 and the levels of antiviral genes following poly(I:C) stimulation. Utilizing reporter plasmids, we elucidated the role of miR-1388 in the antiviral signaling pathway activated by TRAF3. By intervening with siRNA-TRAF3, we validated that miR-1388 regulates the expression of antiviral genes and the production of type I interferons (IFN-Is) through its interaction with TRAF3. Collectively, our experiments highlight the regulatory influence of miR-1388 on the IRF3-mediated signaling pathway by targeting TRAF3 post poly(I:C) stimulation. These findings provide compelling evidence for enhancing our understanding of the mechanisms through which fish miRNAs participate in immune responses.

Exposure to high levels of fine particulate matter (PM) over a long period is strongly associated with an increased risk of morbidity and mortality from respiratory diseases. Although PM_2.5 has been demonstrated to cause lung damage, the exact mechanisms are not fully understood. In this study, six-week-old SPF-grade SD rats were used as an experimental model for PM_2.5 exposure via the endotracheal drip method. A library of circRNAs in rat lung tissues was constructed, and 16,020 circRNAs were successfully predicted, with the highest percentage being of the all-exon type. Validation of the screened differentially expressed circRNAs (DEcircRNAs) was performed using an RNase R digestion assay, Sanger sequencing, and RT-qPCR. In addition, bioinformatics analyses were used to predict the potential miRNA binding sites of the circRNAs and the target genes of miRNAs. A circRNA-miRNA-mRNA regulatory network was constructed and validated through miRNA pull-down experiments. The results showed that exposure to PM_2.5 significantly altered the expression profile of circRNAs in rat lung tissue. The DEcircRNAs and their host genes were found to be primarily associated with physiological processes such as neuromuscular regulation. The constructed circRNA-miRNA-mRNA regulatory network indicated that circRNA4503, circRNA4511, and ciRNA131 (asso-type circRNA131) can adsorb miR-340-5p via the ceRNA mechanism. This process regulates the expression of the target genes DMD, HECW2, and SGIP1, which play a role in the pathological processes of lung diseases. In conclusion, this study establishes a new theoretical foundation for understanding the molecular mechanisms underlying PM_2.5-induced lung injury.