Search Results (627)

Spurred by the enormous therapeutic success of glucagon-like peptide-1 receptor (GLP-1R) agonists (GLP1-RAs) against diabetes and obesity, glucagon family receptor pharmacology has garnered a tremendous amount of interest. Glucagon family receptors, e.g., the glucagon receptor itself (GCGR), the GLP-1R, and the glucose-dependent insulinotropic peptide receptor (GIPR), belong to the incretin receptor superfamily, i.e., receptors that increase blood glucose-dependent insulin secretion. All incretin receptors are class B1 G protein-coupled receptors (GPCRs), coupling to the G_s type of heterotrimeric G proteins which activates adenylyl cyclase (AC) to produce cyclic adenosine monophosphate (cAMP). Most GPCRs undergo desensitization, i.e., uncouple from G proteins and internalize, thanks to interactions with the βarrestins (arrestin-2 and -3). Since the βarrestins can also mediate their own G protein-independent signaling, any given GPCR can theoretically signal (predominantly) either via G proteins or βarrestins, i.e., be a G protein- or βarrestin-“biased” receptor, depending on the bound ligand. A plethora of experimental evidence suggests that the GLP-1R does not undergo desensitization in physiologically relevant tissues in vivo, but rather, it produces robust and prolonged cAMP signals. A particular property of constant cycling between the cell membrane and caveolae/lipid rafts of the GLP-1R may underlie its lack of desensitization. In contrast, GIPR signaling is extensively mediated by βarrestins and the GIPR undergoes significant desensitization, internalization, and downregulation, which may explain why both agonists and antagonists of the GIPR exert the same physiological effects. Here, we discuss this evidence and make a case for the GLP-1R being a phenotypically or functionally G_s-selective receptor. We also discuss the implications of this for the development of GLP-1R poly-ligands, which are increasingly pursued for the treatment of obesity and other diseases. Full article

Objectives: Plasmid-mediated AmpC beta-lactamases represent a growing clinical concern in Enterobacterales, with challenges in diagnostic approaches, limited data on clinical outcomes, and our incomplete understanding of their regulatory mechanisms warranting the need for further investigation. Methods: This retrospective study examined the genomic and clinical characteristics of cefoxitin-non-susceptible, ceftriaxone-susceptible Escherichia coli and Klebsiella pneumoniae bloodstream isolates collected from a tertiary hospital in Singapore. Whole-genome sequencing was performed to detect ampC genes, subtypes, and associated regulatory elements. Results: Among 108 cefoxitin-non-susceptible isolates, only 15 (13.9%) harboured plasmid-mediated ampC, suggesting that cefoxitin non-susceptibility alone in ceftriaxone susceptible isolates was not predictive of ampC carriage. All plasmid-ampC isolates were from the bla_DHA-1 subtype and carried ampR, a known transcriptional regulator of inducible beta-lactamase expression. Notably, five non-ampC carrying Klebsiella isolates displayed truncations in ompK35 and ompK36, which could potentially contribute to reduced cefoxitin susceptibility via porin loss. Conclusions: These findings underscore the limited diagnostic utility of cefoxitin susceptibility testing for detecting plasmid-mediated ampC producers and highlight the clinical relevance of regulatory genes such as ampR in mediating inducible resistance. The routine incorporation of molecular diagnostics or genome sequencing may be necessary to improve detection accuracy and inform antimicrobial stewardship strategies. Full article

FP is a detrimental behavior for chickens, ducks, and geese associated with numerous physiological and neurobiological characteristics, which have been identified in many species as regulated by the gut microbiota. However, it is unknown whether and how gut microbiota influences FP by regulating neurotransmitter systems in geese. This study aimed to investigate the phenotypic correlation between feather pecking and changes in physiological, neurobiological, and gut microbiota profiles in gosling. Three behavioral phenotypes were observed in goslings, including severe feather peckers (SFPs), victims of SFPs, and non-peckers (NFPs). The significantly lower feather scores and body weights were observed in victims compared to both SFPs and NFPs (p < 0.05). Regarding the physiological phenotype, victims had higher dopamine (DA) levels than NFPs, and SFPs had lower 5-hydroxytryptamine (5-HT) in the serum than NFPs (p < 0.001), with intermediate 5-HT levels in victims. Victims had lower glutathione peroxidase (GSH-Px) compared to SFPs and NFPs (p < 0.05). Moreover, higher mRNA expression levels of HTR1A, SLC6A4, and TPH2 in the 5-HT metabolic pathway were detected in NFPs than those in SFPs and victims (p < 0.05). In addition, regarding gut microbiota measured by 16S rRNA sequencing, SFPs had lower diversity and comparable cecal microbiota compared to victims and NFPs. Proteobacteria, Verrucomicrobia, Ruminococcus spp., and Bilophila spp. were enriched in SFPs, while Bacteroides and Parabacteroides were enriched in NFPs. From the predicted bacterial functional genes, the cAMP signaling pathway, cGMP–PKG signaling pathway, and pyruvate metabolism were activated in SFPs. The correlation analysis revealed that the genera Bacteroides spp. were associated with differences in 5-HT metabolism between the SFPs and NFPs. In summary, differences in the cecal microbiota profile and 5-HT metabolism drive FP phenotypes, which could be associated with the reduced gut abundance of the genera Bacteroides spp. Full article

Crustins are a family of cysteine-rich antimicrobial peptides (AMPs), predominantly found in crustaceans, and play important roles in innate immunity. However, among the many reported crustins, few studies have explored their immunomodulatory functions. In this study, we investigated the immune function of a type I crustin (LvCrustinIa-2) in Litopenaeus vannamei, with particular emphasis on comparing the roles of its different domains. LvCrustinIa-2 possesses cationic patchy surface and amphipathic structure, and its expression was significantly induced in hemocytes after pathogen challenge. Both the recombinant LvCrustinIa-2 (rLvCrustinIa-2) and its whey acidic protein (WAP) domain (rLvCrustinIa-2-WAP) exhibited significant inhibitory activities against the tested Gram-positive bacteria. They also showed binding affinity not only for Gram-positive bacteria but also for Gram-negative bacteria. Furthermore, rLvCrustinIa-2 induced membrane leakage and structure damage in the target bacteria. Notably, chemotaxis assays revealed that rLvCrustinIa-2 and the synthetic cysteine-rich region (LvCrustinIa-2-CR) significantly enhanced the chemotactic activity of shrimp hemocytes in vitro. Knockdown of LvCrustinIa-2 triggered significant transcriptional activation of genes involved in calcium transport, inflammation, redox regulation, and NF-κB pathway. Taken together, these findings elucidate the distinct roles of the cysteine-rich region and WAP domain in type Ia crustin and provide the first evidence of a crustacean AMP with chemotactic and immunomodulatory activities. Full article

Background/Objectives: Contextual memory associated with methamphetamine (METH) use contributes to relapse and persistence of addiction. Angiotensin II type 1 receptor (AT1R) signaling has been implicated in drug reinforcement. LCZ696, a clinically used combination of sacubitril (a neprilysin inhibitor) and valsartan (an AT1R antagonist), may interfere with METH-associated memory through the modulation of dopaminergic pathways. Methods: Male C57BL/6J mice were tested in a conditioned place preference (CPP) paradigm to assess the effects of LCZ696, sacubitril (AHU377), and valsartan on METH-induced memory expression and reinstatement. Synaptic plasticity in the nucleus accumbens (NAc) was examined by assessing the levels of synaptophysin (Syp) and postsynaptic density protein 95 (Psd95), as well as dendritic spine density. Dopaminergic signaling in the ventral tegmental area (VTA) was evaluated via ELISA, Western blotting, and chromatin immunoprecipitation (ChIP), targeting cAMP response element-binding protein (Creb) binding to the tyrosine hydroxylase (Th) promoter. To further assess the role of Th, an adeno-associated virus (AAV9) carrying a CRISPR-Cas9-based sgRNA targeting Th (AAV9-Th-sgRNA) was microinjected into the VTA. Results: LCZ696 and valsartan significantly reduced METH-induced CPP and reinstatement. LCZ696 reversed METH-induced synaptic and dopaminergic alterations and suppressed Creb-mediated Th transcription. Th knockdown attenuated both CPP acquisition and relapse. Conclusions: LCZ696 disrupts METH-associated contextual memory by modulating dopaminergic signaling and Creb-dependent Th expression, supporting its potential as a treatment for METH use disorder. Full article

Prolactin is a polypeptide hormone that plays a critical role in male reproduction. However, the underlying mechanisms of prolactin-regulated testosterone secretion and the roles of lncRNAs in this process remain unclear. We performed a comprehensive analysis of the testicular tissues of cashmere goats with different prolactin levels by means of RNA-sequencing. Then, we constructed a lncRNA–miRNA–mRNA interaction network by integrating previously submitted testicular mRNA sequencing data. We identified a novel lncRNA named lncRWDD3 and investigated its effects on testosterone synthesis in the Leydig cells of cashmere goat. The primary Leydig cells were used to explore the biological function of lncRWDD3/miR-1388-5p/NPY1R in vitro. This study found that 200 ng/mL of prolactin achieved the highest testosterone secretion in Leydig cells. LncRWDD3 or NPY1R overexpression promoted cAMP levels, testosterone secretion, and related gene expression, while lncRWDD3 or NPY1R interference had the opposite effect. It was found that lncRWDD3 acts on miR-1388-5p as a ceRNA, and neuropeptide Y receptor Y1 (NPY1R) was confirmed to be a target of chi-miR-1388-5p. Our research shows that prolactin regulates the testicular function of cashmere goats via the lncRNA–miRNA–mRNA ceRNA network, and lncRWDD3 acts as a ceRNA to activate NPY1R/cAMP signaling via the sponging of miR-1388-5p in order to govern testosterone synthesis in the Leydig cells of cashmere goats. Our results provide insights for future studies on the molecular mechanism of the prolactin regulation of testicular function in goats. Full article

The large yellow croaker, or Larimichthys crocea, is highly prized for its golden color and nutritional content. The purpose of this study was to investigate the differences in body composition, mucus biochemical indices and body color in five strains of large yellow croakers (body weight: 347.01 ± 5.86 g). To conduct genetic diversity analyses of the populations, a total of 50 tailfin samples were randomly chosen from the following populations of large yellow croakers: wild (LYC1), Dai-qu population (LYC2), Yongdai 1 (LYC3), Min-yuedong population (LYC4), and Fufa 1 (LYC5). The findings demonstrated that the LYC3 group’s pigment contents, crude protein, crude lipid, and chromatic values were comparable to those of the LYC1 group (p > 0.05). There was no significant difference between the LYC1 and LYC5 groups’ mucus superoxide dismutase (SOD) and catalase (CAT) activities (p > 0.05). The alkaline phosphatases (ALP), acid phosphatases (ACP), and lysozyme (LYS) activities of the mucus in the LYC1 group were not significantly different from the LYC3 group (p > 0.05). The back skin mRNA expressions of tyrosinase (tyr), tyrosinase-related protein 1 (tyrp1), dopachrome tautomerase (dct), microphtalmia-associated transcription factor (mitf), and melanocortin 1 receptor (mc1r) were significantly up-regulated in the LYC2 and LYC4 groups compared to the LYC1, LYC3, and LYC5 groups (p < 0.05). Forkhead box d3 (foxd3), paired box 3 (pax3), purine nucleoside phosphorylase 4a (pnp4a), aristaless-like homeobox 4a (alx4a), cAMP dependent protein kinase (pka), anaplastic lymphoma kinase (alk), leukocyte receptor tyrosine kinase (ltk), and colony stimulating factor (fms) were among the mRNA expressions of the abdominal skin in the LYC1, LYC3, and LYC5 groups significantly higher than those in the LYC2 and LYC4 groups (p < 0.05). In conclusion, the LYC3 group’s crude protein, crude lipid, carotenoid, and lutein contents were most similar to those of the large yellow croaker found in the wild. Furthermore, the molecular mechanism underlying the variations in body color among the various strains of large yellow croakers was supplied for additional research. Full article

The development of novel antimicrobial peptides (AMPs) with broad-spectrum activity represents a promising strategy to overcome multidrug resistance in pathogenic bacteria. In this study, we investigated the antimicrobial activity of three designed peptides—R44K^S*, V31K^S*, and R23F^S*—engineered to incorporate an amyloidogenic fragment from the S1 protein of Staphylococcus aureus and one or two cell-penetrating peptide (CPP) fragments to enhance cellular uptake. The antimicrobial efficacy of these peptides and their combinations was assessed against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and Bacillus cereus. The results demonstrated that all three peptides exhibited significant antibacterial activity in a concentration-dependent manner, with R44K^S* being the most potent. Peptide combinations, particularly V31K^S*/R23F^S* and R44K^S*/V31K^S*, showed enhanced inhibitory effects and reduced minimum inhibitory concentrations (MICs), suggesting synergistic or additive interactions. Fractional inhibitory concentration index (FICI) analysis confirmed that most combinations exhibited synergy or additive effects. These findings highlight the potential of CPP-modified peptides as antimicrobial agents and underscore the importance of optimizing peptide combinations for therapeutic applications. Full article

This study investigated thermophilic bacterial communities from two Algerian hot springs: Hammam Debagh (94–98 °C), recognized as the second hottest spring in the world, and Hammam Bouhadjar (61–72 °C), one of the hottest in northwest Algeria. Thirty isolates were obtained, able to grow between 45 °C and 80 °C, tolerating pH 5.0–12.0 and NaCl concentrations up to 3%. Colonies displayed diverse morphologies, from circular and smooth to star-shaped and Saturn-like forms. All isolates were characterized as Gram-positive, catalase-positive rods or filamentous bacteria. Identification by MALDI-TOF, rep-PCR and 16S rRNA sequencing classified them mainly within Bacillus, Brevibacillus, Aneurinibacillus, Geobacillus, and Aeribacillus, with Geobacillus predominating. Rep-PCR provided higher resolution, revealing intra-species diversity overlooked by MALDI-TOF MS and 16S rRNA. A subset of six isolates, mainly Geobacillus spp., was selected based on phenotypic and genotypic diversity and tested for antimicrobial activity against thermophilic target isolates from the same hot spring environments. Strong inhibition zones (~24 mm) were observed, with Geobacillus thermoleovorans B8 displaying the highest activity. Optimization on Modified Nutrient Agar medium with Gelrite enhanced antimicrobial production and inhibition clarity. These findings highlight the ecological and biotechnological significance of thermophilic bacteria from Algerian geothermal ecosystems. While this study focused on microbial interactions within thermophilic communities, the promising inhibitory profiles reported here provide a foundation for future research targeting foodborne and antibiotic-resistant pathogens, as part of broader efforts in biopreservation and sustainable antimicrobial development. Full article

Synbiotics can be used to reduce intestinal inflammation and mitigate dysbiosis in dogs with chronic inflammatory enteropathy (CIE). Prior research has not assessed the colonic mucosal ultrastructure of dogs with active CIE treated with synbiotics, nor has it determined a possible association between morphologic injury and signaling pathways. Twenty client-owned dogs diagnosed with CIE were randomized to receive either a hydrolyzed diet (placebo; PL) or a hydrolyzed diet supplemented with synbiotic-IgY (SYN) for 6 weeks. Endoscopic biopsies of the colon were obtained for histopathologic, ultrastructural, and molecular analyses and were compared before and after treatment. Using transmission electron microscopy (TEM), an analysis of the ultrastructural alterations in microvilli length (MVL), mitochondria (MITO), and rough endoplasmic reticulum (ER) was compared between treatment groups. To explore potential signaling pathways that might modulate MITO and ER stress, a transcriptomic analysis was also performed. The degree of mucosal ultrastructural pathology differed among individual dogs before and after treatment. Morphologic alterations in enterocytes, MVL, MITO, and ER were detected without significant differences between PL and SYN dogs prior to treatment. Notable changes in ultrastructural alterations were identified post-treatment, with SYN-treated dogs exhibiting significant improvement in MVL, MITO, and ER injury scores compared to PL-treated dogs. Transcriptomic profiling showed many pathways and key genes to be associated with MITO and ER injury. Multiple signaling pathways and their associated genes with protective effects, including fibroblast growth factor 2 (FGF2), fibroblast growth factor 7 (FGF7), fibroblast growth factor 10 (FGF10), synaptic Ras GTPase activating protein 1 (SynGAP1), RAS guanyl releasing protein 2 (RASGRP2), RAS guanyl releasing protein 3 (RASGRP3), thrombospondin 1 (THBS1), colony stimulating factor 1 (CSF1), colony stimulating factor 3 (CSF3), interleukin 21 receptor (IL21R), collagen type VI alpha 6 chain (COL6A6), ectodysplasin A receptor (EDAR), forkhead box P3 (FoxP3), follistatin (FST), gremlin 1 (GREM1), myocyte enhancer factor 2B (MEF2B), neuregulin 1 (NRG1), collagen type I alpha 1 chain (COL1A1), hepatocyte growth factor (HGF), 5-hydroxytryptamine receptor 7 (HTR7), and platelet derived growth factor receptor beta (PDGFR-β), were upregulated with SYN treatment. Differential gene expression was associated with improved MITO and ER ultrastructural integrity and a reduction in oxidative stress. Conversely, other genes, such as protein kinase cAMP-activated catalytic subunit beta (PRKACB), phospholipase A2 group XIIB (PLA2G12B), calmodulin 1 (CALM1), calmodulin 2 (CALM2), and interleukin-18 (IL18), which have harmful effects, were downregulated following SYN treatment. In dogs treated with PL, genes including PRKACB and CALM2 were upregulated, while other genes, such as FGF2, FGF10, SynGAP1, RASGRP2, RASGRP3, and IL21R, were downregulated. Dogs with CIE have colonic ultrastructural pathology at diagnosis, which improves following synbiotic treatment. Ultrastructural improvement is associated with an upregulation of protective genes and a downregulation of harmful genes that mediate their effects through multiple signaling pathways. Full article

The escalating crisis of antimicrobial resistance in aquaculture, driven by the indiscriminate use of antibiotics, underscores the urgent need to develop novel anti-infective agents. This study addresses this requirement by investigating cysteine-rich antimicrobial peptides (AMPs) in understudied crustacean species. A cysteine-rich AMP, designated PpRcys1, was identified and characterized from the genome of Pollicipes pollicipes. PpRcys1 comprises 104 amino acids, with 85 residues forming the mature peptide region, and exhibits random coils, a CSαβ-fold, and one β-sheet. Our findings demonstrated that recombinant PpRcys1 (rPpRcys1) possesses broad-spectrum antimicrobial activity against three Gram-positive bacteria (Staphylococcus aureus, Bacillus sp. T2, and Streptococcus agalactiae) and four Gram-negative bacteria (Aeromonas hydrophila, Escherichia coli, Vibrio alginolyticus, and Acinetobacter sp. L3), with minimum inhibitory concentrations ranging from 8 to 32 μM. It exerts antimicrobial effects by inducing membrane disruption without impacting bacterial protease activity, DNA migration, or respiratory chain reductase activity. Further investigation is warranted to determine whether it can target and interfere with intracellular bacterial processes. Our discovery and characterization of this novel AMP provide a promising foundation for its development as an alternative to antibiotics. Full article

The yak is a classic grazing livestock species on the Qinghai–Tibet Plateau, and fat deposition is indispensable for its survival and metabolism. Coding and non-coding RNAs (ncRNAs) play an important role in regulating fat deposition in livestock. In this study, the expression of mRNAs, lncRNAs, miRNAs, and circRNAs in the subcutaneous fat of yaks under grazing and stall feeding was measured using whole-transcriptome sequencing technology. A total of 677 differentially expressed (DE) mRNAs, 120 DE lncRNAs, 2216 DE circRNAs, and 15 DE miRNAs were identified, and their biological function was explored using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Co-expression RNA (ceRNA) networks between DE ncRNAs and DE mRNAs were further constructed, and the crucial RNAs and signal pathways regulating fat deposition in yaks were obtained. The effect of mRNAs and ncRNAs on fat deposition in yaks mainly depended on the PPAR, PI3K–Akt, and cAMP signaling pathways, and the regulatory pathways TCONS00042948, TCONS00012083/bta-miR-2316/MCAT, and NR4A3 may be critical in this process. This study provides some theoretical basis for breeding yak species and promotes improvements in yak production. Full article

Protein kinase A (PKA), commonly referred to as cAMP-dependent protein kinase, exists as a heterotetramer composed of two catalytic (C) and regulatory subunits (R). This versatile kinase exhibits regulatory functions in various biological processes including growth, division, and differentiation. Although PKA is well established as a master regulator of oocyte maturation across species, its functional role in insect parthenogenesis has remained enigmatic. Here, we systematically investigated the regulatory effect of PKA in the induction of parthenogenesis in model lepidopteran Bombyx mori. Our findings demonstrated an inverse correlation between PKA activity and parthenogenetic induction efficiency in silkworms. Notably, PKA activation resulted in delayed embryonic development, whereas PKA-C1 knockdown disrupted normal cell cycle progression. These results indicated that maintaining appropriate PKA activity is essential for ensuring proper cell division process, especially in the successful induction of silkworm parthenogenesis. The evolutionary conservation of PKA across species, coupled with its critical regulatory role in parthenogenesis, positions this kinase as a promising molecular target for breeding design. Our findings establish a foundation for developing silkworm strains with enhanced parthenogenetic capacity through PKA modulation, thereby facilitating the preservation of elite production traits. These results provide novel mechanistic insights into parthenogenesis while demonstrating the potential application of PKA regulation in both genetic studies and breeding programs. Full article

Meat quality traits, particularly WHC and tenderness, are pivotal for consumer satisfaction and economic value in the sheep industry. However, their genetic regulatory mechanisms remain unclear. We used RNA-Seq and WGCNA to identify genes regulating WHC and tenderness. Sixty longissimus thoracis samples were classified into high/low WHC (HWHC vs. LWHC) and high/low tenderness (HTN vs. LTN) groups. Comparative transcriptomics identified 270 differentially expressed genes (DEGs) linked to WHC, enriched in pathways like the regulation of the ATP metabolic process and the inhibition of canonical Wnt signaling. Key DEGs (e.g., SORBS1, FOXO1, PDE4B, CDH1) correlated significantly with WHC-associated traits. For tenderness, 165 DEGs were identified, including LEP, FABP4, PLIN1, and GLP1R, enriched in PPAR signaling, fat cell differentiation, and cAMP signaling pathways. WGCNA revealed modules associated with WHC and tenderness, with hub genes (ATP2C1, GSKIP, PATL1, PPARA, CYLD) involved in ATP metabolism, lipid biosynthesis, and myofibril assembly. Tissue-specific gene integration prioritized muscle-enriched candidates (METTL21C and ACTC1) with strong trait correlations. Our findings unveil interconnected gene networks governing WHC and tenderness, highlighting some candidate genes as potential biomarkers for precision breeding. This study provides novel insights into the molecular determinants of meat quality, offering actionable targets to enhance mutton production sustainability and consumer appeal. Full article

Enterotoxigenic Escherichia coli (ETEC), a common intestinal pathogen, can colonize the intestines and induce diarrhea in piglets, which brings great economic losses to the swine industry. Antibiotics are recommended to the treatment for diarrhea caused by ETEC in weaned piglets. However, with the emergence and spread of multidrug-resistant ETEC, there is an urgent need to develop alternatives to antibiotics. Due to the unique antibacterial mechanism of targeting bacterial membranes, antimicrobial peptides (AMPs) are promising candidates. In this study, the activity of crude recombinant porcine β-defensin 2 (rPBD2) expressed in Pichia pastoris (P. pastoris) was measured in vitro. Mice infected with ETEC were orally administered 16, 8, and 4 AU crude rPBD2 for 7 consecutive days to evaluate its anti-infective activity in vivo. The results showed that in addition to broad antibacterial activity against Gram-positive and -negative bacteria, crude rPBD2 displayed high tolerance to temperatures ranging from 20 to 60 °C, a broad range of pH, trypsin, pepsin, and physiological concentrations of salts. In an ETEC-induced mouse model, the oral administration of crude rPBD2 decreased diarrhea scores and the intestinal/carcass ratio and alleviated body weight loss. Additionally, crude rPBD2 decreased bacterial loads in stools and the colon (HP group), and the levels of serum pro-inflammatory cytokines IL-6 (HP group) and TNF-α (HP and MP groups), and increased the villus height and the ratio of villus height to crypt depth (VH/CD) in the ileum (HP and MP groups). Our study provides a cost-effective way for PBD2 production and identifies it as a promising candidate to combat ETEC-induced infection. Full article