Search Results (290)

Lipopolysaccharide (LPS), the defining outer membrane component of Gram-negative bacteria, is a potent immunostimulant recognized by Toll-like receptor 4 (TLR4). While extensively studied for its roles in immune activation and barrier disruption, the potential function of LPS as a developmental cue remains largely unexplored. By leveraging Caenorhabditis elegans and its genetic and gnotobiotic advantages, we screened a panel of Escherichia coli LPS biosynthesis mutants. This screen revealed that the loss of outer core glycosylation in the ∆rfaG mutant causes significant developmental delay independent of bacterial metabolism. Animals exhibited developmental delay that was rescued by exogenous LPS or amino acid supplementation, implicating that LPS triggers nutrient-sensing signaling. Mechanistically, this developmental arrest was mediated by the host FOXO transcription factor DAF-16, which is the key effector of insulin/IGF-1 signaling (IIS). Our findings uncover an unprecedented role for microbial LPS as a critical regulator of host development, mediated through conserved host IIS pathways, fundamentally expanding our understanding of host–microbe crosstalk. Full article

Background/Objectives: While ocular albinism (OA) is usually associated with reduced vision, nystagmus, and foveal hypoplasia, there is phenotypic variability in iris and fundus hypopigmentation. Hemizygous pathogenic/likely pathogenic (P/LP) variants in GPR143 at X: 151.56–151.59 have been shown in the literature to be associated with OA. The purpose of this study was to report the case of a Hispanic male with X-linked inherited OA associated with a hemizygous GPR143 variant and to review the literature relating to genotype–phenotype associations with GPR143 and OA. Methods: After consent to an IRB-approved protocol, a 14-year-old Hispanic male patient with OA and his parents underwent whole genome sequencing (WGS) in 2023. Two maternal uncles with nystagmus underwent targeted variant testing in 2024. A literature review of reported GPR143 variants was completed. Results: A male with reduced visual acuity, infantile-onset nystagmus, foveal hypoplasia, and iris hypopigmentation was identified to have the variant GPR143, c.455+3A>G, which was also present in his mother and two affected maternal uncles. This variant has been previously identified in other Hispanic patients of Mexican descent. Additionally, 127 variants were identified in the literature and reported to be associated with OA. All patients had reduced visual acuity (average 0.71 ± 0.23 logMAR), 99% had nystagmus, 97% foveal hypoplasia, 79% fundus hypopigmentation, and 71% iris hypopigmentation. Of those patients with reported optotype best corrected visual acuity (BCVA), eight (9%) had VA from 20/25 to 20/40, 24 (24%) had VA from 20/50 to 20/80, and 63 (67%) had VA from 20/100 to 20/200. The most frequent type of variant was missense (31%, n = 39). Frameshift and nonsense variants were associated with the lowest rates of iris hypopigmentation (50% [n = 11] and 44% [n = 8], respectively; p = 0.0068). Conclusions: This case represents phenotypic variability of GPR143-associated OA and highlights the importance of repeat genetic testing and independent analyses of test results for accurate variant classification, particularly in non-White and Hispanic patients. Further studies in more diverse populations are needed to better develop genotype–phenotype associations for GPR143-associated OA. Full article

Background: The profile of germline genetic variants among colorectal cancer patients in Panama has not yet been explored. Methods: We recruited 95 patients with colorectal cancer in an Oncology Reference Hospital Unit in the Azuero region of central Panama, which exhibited the highest prevalence of colorectal cancer in Panama. DNA analysis was performed with a panel of 113 genes with germline mutations for cancer (TruSight^® Cancer Sequencing Panel from Illumina, San Diego, CA, USA). Results: Among the 95 cases, 10 pathogenic/likely pathogenic variants (P/LP) were identified in the MUTYH, TP53, CHEK2, PALB2, ATM, and BARD1 genes, representing 10% of the total. The variant 1103G>A (p.Gly368Asp) in MUTYH was the most prevalent. The variant at c.1675_1676delCAinsTG (p.Gln559Ter) in PALB2 is new and is reported for the first time in this study. Variants were most frequently detected in the MUTYH and CHEK2 genes, affecting four and two patients, respectively. Notably, none of the 95 Panamanian patients in the initial colorectal cancer cohort had mutations in mismatch repair (MMR) genes. These genes are among the most frequently mutated in other cohorts around the world. Conclusions: The atypical profile of germline genetic variants in this population may be related to the unique characteristics of the Azuero population in Panama’s central region. This profile may partly explain the high prevalence of colorectal cancer among its inhabitants. Full article

Background: Copy number variants of uncertain significance (CNVus) from chromosome microarray analysis (CMA) presents unresolved challenges for clinical geneticists, genetic counselors, and patients. We performed a systematic reevaluation of reported CNVus and reanalysis of selected CNVus by whole genome sequencing (WGS) to assess the diagnostic value and clinical impact on CNVus reclassification. Methods: We retrospectively reviewed 5277 consecutive pediatric cases by CMA from the Yale Clinical Cytogenetics Laboratory over a 13-year period. Reevaluation was performed on all reported CNVus following current ACMG/ClinGen guidelines. Reanalysis by WGS was applied to selected cases for reclassification of CNVus. Results: A total of 567 CNVus from 480 cases were reported, which accounted for 9.1% of pediatric cases. A total of 4 CNVus in 4 cases (0.8%, 4/480) were reclassified to pathogenic/likely pathogenic CNVs (pCNVs/lpCNVs); while 23 CNVus in 23 cases (4.8%, 23/480) were reclassified to benign/likely benign CNVs (bCNVs/lbCNVs). The overall rate of reclassification was 5.6%. WGS performed on selected cases further defined breakpoints and ruled out additional causative genetic variants. Conclusions: The results from this study demonstrated the diagnostic value of periodic reevaluation of CNVus and reanalysis by WGS in an interval of 3–5 years and provided evidence to support standardized laboratory reevaluation and reanalysis. Full article

Periodontitis is a multifactorial disease linked to host immune response and genetic predisposition. The TLR4 Asp299Gly single-nucleotide polymorphism (SNP, rs4986790) has been associated with altered responses to bacterial lipopolysaccharide (LPS) and may influence susceptibility to inflammatory diseases. Given the central role of TLR4 in innate immune recognition of periodontal pathogens, this study investigates the role of rs4986790 in modulating susceptibility to periodontal inflammatory destruction. A total of 1410 individuals from four populations were genotyped, with findings indicating a significant protective effect of the polymorphic allele. Functional assays demonstrated enhanced IL-8 secretion and increased sensitivity to CD14 inhibition in cells expressing the variant receptor. These results suggest that rs4986790 modifies the LPS response via TLR4, potentially offering protection against periodontal breakdown. Full article

Background/Objectives: Obesity is associated with cardiovascular disease worldwide. An increased lipoprotein A (LpA) level is an independent risk factor for cardiovascular disease in children. Genetic polymorphisms of the LPA gene may play an important role in susceptibility to obesity. The aim of this study was to investigate the association of LPA rs10455872 polymorphism with the risk and clinical phenotypes of childhood obesity. Methods: This study included 103 children with obesity and 77 healthy controls. Genotyping of the LPA rs10455872 polymorphism was performed using real-time PCR. Results: The genotype distributions of the LPA rs10455872 polymorphism did not differ significantly between children with obesity and healthy children (p = 0.563). A marked difference in insulin levels was observed between children with obesity carrying the AG (16.90 IU/mL) and AA (25.57 IU/mL) genotypes. A marked difference was also observed in CRP levels between children with obesity with the AG (2.31 mg/L) and AA (4.25 mg/L) genotypes. After correcting for multiple comparisons using the false discovery rate (FDR), significant differences were found between AG and AA genotypes in vitamin B12 (adjusted p = 0.024). Serum iron showed a borderline association (adjusted p = 0.072). A statistically significant correlation was found between the metabolic syndrome index and body fat ratio among children with obesity with the AA genotype (p = 0.028). Conclusions: Although limited by the small number of children with obesity with the AG genotype, some differences were noted between the AG and AA genotypes. These exploratory findings require further investigation in adequately powered studies. In children with obesity with the AA genotype, the metabolic syndrome index increases as the body fat ratio increases. Full article

The mitochondrial regulator MNRR1 is reduced in several pathologies, including the mitochondrial heteroplasmic disease MELAS, and genetic restoration of its level normalizes the pathological phenotype. Here, we investigate the upstream mechanism that reduces MNRR1 levels. We have identified the hypoxic regulator HIF2α to bind the MNRR1 promoter and inhibit transcription by competing with RBPJκ. In MELAS cells, there is a pseudohypoxic state that transcriptionally induces HIF2α and stabilizes HIF2α protein. MELAS cybrids harboring the m.3243A > G mutation display reduced levels of prolyl hydroxylase 3 (PHD3), which contributes to the HIF2α stabilization. These results prompted a search for compounds that could increase MNRR1 levels pharmacologically. The screening of a 2400-compound library uncovered the antifungal drug nitazoxanide and its metabolite tizoxanide as enhancers of MNRR1 transcription. We show that treating MELAS cybrids with tizoxanide restores cellular respiration, enhances mitophagy, and, importantly, shifts heteroplasmy toward wild-type mtDNA. Furthermore, in fibroblasts from MELAS patients, the compound improves mitochondrial biogenesis, enhances autophagy, and protects from LPS-induced inflammation. Mechanistically, nitazoxanide reduces HIF2α levels by increasing PHD3. Chemical activation of MNRR1 is thus a potential strategy to improve mitochondrial deficits seen in MELAS. Finally, our data suggests a broader physiological pathway wherein two proteins, induced under severe (1% O2; HIF2α) and moderate (4% O2; MNRR1) hypoxic conditions, regulate each other inversely. Full article

The progression of type 2 diabetes mellitus (T2DM) is shaped by a multifaceted interplay among genetic, behavioral, and environmental factors, alongside gut dysbiosis. Cinnamon, being abundant in polyphenols and flavonoids, shows significant antioxidant effects. Studies have substantiated that cinnamon contributes to the management of glucose and lipid metabolism. However, the anti-diabetic efficacy of cinnamon is not completely understood. The objective of this research was to clarify the anti-diabetic mechanism associated with cinnamon extract through a combination of chemical profiling, network pharmacology, and in vivo investigations. The results indicated that 32 chemical ingredients, including quercetin, were identified through UPLC-Q-TOF-MS. Network pharmacology revealed that 471 targets related to 14 compounds were screened. The analysis of GO enrichment revealed that the primary pathways were notably enhanced in the metabolism of insulin and glucose. In vivo analyses showed that cinnamon could effectively alleviate hyperglycemia, insulin resistance, and lipid metabolism abnormalities via increased relative abundance of Akkermansia and Ligilactobacillus at the genus level and a decreased Firmicutes/Bacteroidetes ratio at the phylum level. Moreover, cinnamon reduced the serum levels of lipopolysaccharide (LPS) and proinflammatory cytokines (IL-6 and TNF-α) and significantly increased the colon Zonula occludens-1 (ZO-1) and occludin protein levels. It was also observed that cinnamon improved the fecal SCFA levels (acetic, propionic, butyric, valeric and caproic acid), while also modifying the bile acid (BA) profile and increasing the conjugated-to-unconjugated BA ratio. The Western blotting analysis further demonstrated that cinnamon activated intestinal FXR/FGF15 and hepatic PI3K/AKT signaling pathways. In summary, the finding confirmed that cinnamon ameliorated glucose and lipid metabolism disorders by safeguarding the intestinal barrier and modulating the gut microbiota and metabolites, thereby activating intestinal FXR/FGF15 and hepatic PI3K/AKT signaling pathways. Full article

Calreticulin is a highly conserved and multifunctional molecular chaperone ubiquitously expressed in humans and animals. Beyond its well-established roles in calcium homeostasis, protein folding, and immune regulation, recent studies in aquatic species have suggested a previously unrecognized antimicrobial function of calreticulin. These findings raise the question of whether calreticulin also exerts antibacterial activity in terrestrial mammals, which has not been systematically investigated to date. To address this knowledge gap, we successfully constructed and expressed recombinant goat calreticulin using the Pichia pastoris expression system, yielding a protein of over 99% purity that predominantly exists in dimeric form. Functional assays demonstrated that both recombinant goat and human calreticulin exhibited preliminary inhibitory activity against Escherichia coli, Salmonella typhimurium, and Pasteurella multocida. Calreticulin was capable of binding to these three bacterial species as well as bacterial lipopolysaccharides (LPS). Notably, in the presence of Ca²⁺, calreticulin induced bacterial aggregation, indicating a potential mechanism for limiting bacterial dissemination and proliferation. Given the high anatomical, genetic, and physiological similarity between goats and humans—particularly in respiratory tract structure and mucosal immune function—neonatal goats were selected as a relevant model for evaluating the in vivo antimicrobial efficacy of calreticulin. Accordingly, we established an intranasal infection model using Pasteurella multocida to assess the protective role of calreticulin against respiratory bacterial challenge. Following infection, calreticulin expression was markedly upregulated in the nasal mucosa, trachea, and lung tissues. Moreover, intranasal administration of exogenous calreticulin significantly alleviated infection-induced pathological injury to the respiratory system and effectively decreased bacterial loads in infected tissues. Collectively, this study systematically elucidates the antimicrobial activity of calreticulin in a mammalian model and highlights its potential as a natural immune effector, providing novel insights for the development of host-targeted antimicrobial strategies. Full article

Vibrio species are among the primary pathogenic bacteria affecting abalone aquaculture, posing significant threats to farming practices. Current clinical control predominantly relies on antibiotics, which can result in antibiotic residues in both abalone and the surrounding marine environments. Lactobacillus plantarum (LP) has been shown to release bioactive antagonistic substances and exhibits potent inhibitory effects against marine pathogenic bacteria. This study aimed to screen and characterize the probiotic properties of LP strains isolated from rice wine lees to develop a novel biocontrol strategy against Vibriosis in abalone. The methods employed included selective media cultivation, streak plate isolation, and single-colony purification for strain screening, followed by Gram staining, 16S rDNA sequencing, and phylogenetic tree construction using MEGA11 for identification. The resilience, antimicrobial activity, and in vivo antagonistic efficacy of the strains were evaluated through stress tolerance assays, agar diffusion tests, and animal experiments. The results demonstrated the successful isolation and purification of four LP strains (NDMJ-1 to NDMJ-4). Phylogenetic analysis revealed closer genetic relationships between NDMJ-3 and NDMJ-4, while NDMJ-1 and NDMJ-2 were found to be more distantly related. All strains exhibited γ-hemolytic activity, bile salt tolerance (0.3–3.0%), and resistance to both acid (pH 2.5) and alkali (pH 8.5), although they were temperature sensitive (inactivated above 45 °C). The strains showed susceptibility to most of the 20 tested antibiotics, with marked variations in hydrophobicity (1.91–93.15%) and auto-aggregation (13.29–60.63%). In vitro antibacterial assays revealed that cell-free supernatants of the strains significantly inhibited Vibrio parahaemolyticus, V. alginolyticus, and V. natriegens, with NDMJ-4 displaying the strongest inhibitory activity. In vivo experiments confirmed that NDMJ-4 significantly reduced mortality in abalone infected with V. parahaemolyticus. In conclusion, the LP strains isolated from rice wine lees (NDMJ-1 to NDMJ-4) possess robust stress resistance, adhesion capabilities, and broad antibiotic susceptibility. Their metabolites exhibit significant inhibition against abalone-pathogenic Vibrios, particularly NDMJ-4, which demonstrates exceptional potential as a candidate strain for developing eco-friendly biocontrol agents against Vibriosis in abalone aquaculture. Full article

Lipopolysaccharide (LPS) endotoxin is a well-characterized microbe-associated molecular pattern (MAMP) that forms the outer membrane of both pathogenic and commensal Gram-negative bacteria. It plays a crucial role in triggering inflammatory disorders such as mastitis, acidosis, and septicemia. In heifers, an LPS challenge induces a dynamic stress response, marked by elevated cortisol levels, increased body temperature, and altered immune function. Research indicates that LPS administration leads to a significant rise in cortisol post-challenge. Building on this understanding, the present study aimed to estimate genetic parameters for serum cortisol response to LPS challenge in Holstein heifers and its linear associations with production, health, reproduction, and conformation traits. Additionally, a genome-wide association study (GWAS) was conducted to identify genetic regions associated with cortisol response. A total of 252 animals were evaluated for cortisol response, with correlations estimated between cortisol levels and 55 genomic breeding values for key traits. Genetic parameters and heritability for cortisol response were estimated using Residual Maximum Likelihood (REML) in the Blupf90+ v 2.57 software. Single-Step GWAS (ssGWAS) employing a 10-SNP window approach and 42,123 SNP markers was performed to identify genomic regions that explained at least 0.5% of additive genetic variance. Finally, candidate genes and QTLs located 50 kb up and downstream of those windows were identified. The cortisol response showed significant but weak linear associations with cystic ovaries, body maintenance requirements, lactation persistency, milk yield, and protein yield (p-value ≤ 0.05) and showed suggestive weak linear associations with udder texture, clinical ketosis, heel horn erosion, and milking speed (p-value ≤ 0.15). Cortisol response showed significant additive genetic variance, along with moderate heritability of 0.26 (±0.19). A total of 34 windows explained at least 0.5% of additive genetic variance, and 75 QTLs and 11 candidate genes, comprising the genes CCL20, DAW1, CSMD2, HMGB4, B3GAT2, PARD3, bta-mir-2285aw, CFH, CDH2, ENSBTAG00000052242, and ENSBTAG00000050498, were identified. The functional enrichment analysis allowed us to infer two instances where these gene products could interfere with cortisol production: the first instance is related to the complement system, and the second one is related to the EMT (Epithelium–Mesenchymal Transition) and pituitary gland formation. Among the QTLs, 13 were enriched in the dataset, corresponding to traits related to milk (potassium content), the exterior (udder traits, teat placement, foot angle, rear leg placement, and feet and leg conformation), production (length of productive life, net merit, and type), and reproduction (stillbirth and calving ease). In summary, the cortisol response to LPS challenge in Holstein heifers seems to be moderately heritable and has weak but significant linear associations with important production and health traits. Several candidate genes identified could perform important roles, in at least two ways, for cortisol production, and QTLs were identified close to regions of the genome that explained a significant amount of additive genetic variance for cortisol response. Therefore, further investigations are warranted to validate these findings with a larger dataset. Full article

Background/Objectives: Colistin is a last-resort treatment for Pseudomonas aeruginosa multidrug-resistant infections, but resistance to it is emerging. While colistin resistance in P. aeruginosa is typically associated with chromosomal mutations inducing lipopolysaccharide (LPS) aminoarabinosylation, other mutations unrelated to LPS modifications have been proposed to influence the extent of colistin resistance. Here, we examined whether the genetic background and culture conditions affect the evolution of high-level colistin resistance in this bacterium. Methods: We performed in vitro evolution experiments in the presence or absence of increasing colistin concentrations with two phylogenetically distant reference strains in a standard laboratory medium and in two media mimicking P. aeruginosa growth during lung or systemic infections. Resistance-associated mutations were identified by comparative genomics, and the role of selected mutated genes was validated by allele replacement, deletion, or conditional mutagenesis. Results: Most colistin-resistant mutants carried mutations in genes belonging to four functional groups: two-component systems controlling LPS aminoarabinosylation (PmrAB, PhoPQ), LPS biosynthesis, the production of the polyamine norspermidine, and fatty acid metabolism. No mutation was exclusively and invariably associated with a specific strain or medium. We demonstrated that norspermidine is detrimental to the acquisition of colistin resistance upon PmrAB activation and that impaired fatty acid biosynthesis can promote colistin resistance, even if it increases susceptibility to other antibiotics. Conclusions: The evolution of colistin resistance in P. aeruginosa appeared to be only marginally affected by the genetic background and culture conditions. Notably, mutations in fatty acid biosynthetic genes represent a newly identified genetic determinant of P. aeruginosa colistin resistance, warranting further investigation in clinical isolates. Full article

Phosphorus (P) is an essential nutrient for plant growth, and low-phosphorus (LP) stress significantly limits cotton productivity. Here, we conducted single- and multi-locus genome-wide association studies (GWASs) on four LP-related traits using 419 upland cotton (Gossypium hirsutum L.) accessions genotyped with 2.97 million single-nucleotide polymorphisms (SNPs). Phenotypic analysis reveals substantial variation under LP stress, with LP-SDW showing the highest coefficient of variation (33.69%). The GWASs identified thousands of significant SNPs, including pleiotropic loci associated with multiple traits. Chromosomes A08, D09, and D12 harbored novel associated signals. Multi-locus models significantly enhanced detection sensitivity, identifying 123 SNPs undetected by single-locus approaches. Functional annotations prioritized six candidate genes near associated SNPs, including GhM_A08G1315 (remorin protein) and GhM_D06G1152 (carotenoid cleavage dioxygenase), whose LP-induced expression patterns were validated by qRT-PCR. These genes are implicated in membrane signaling, root architecture modulation, and hormone metabolism. Our findings provide novel genetic insights into LP tolerance and establish a foundation for breeding phosphorus-efficient varieties through marker-assisted selection in cotton. Full article

Dietary modification is a critical tool in the prevention of cardiovascular disease (CVD). While the role of saturated fat (SFA) intake is well established in affecting LDL cholesterol concentrations, diet impacts on lipoprotein(a) (Lp(a)) have been less studied. Lp(a) is a prevalent, strong, and highly heritable risk factor for CVD and a therapeutic target for CVD risk management. While significant insights have been made into the genetic regulation of Lp(a), our understanding of any metabolic impact on Lp(a) by other factors, including diets, is limited. For many years, Lp(a) was not considered to be subject to dietary regulation, but there is now clear evidence of a dietary impact, in particular variability in SFA intake, on Lp(a) concentrations. The present narrative review aims to provide an updated view on dietary regulation of Lp(a), moving beyond studies testing the effect of reducing SFA intake, to include new evidence from clinical trials on the impact of an increased sugar intake and ketogenic diets. In addition to describing an opposite effect of SFA on Lp(a) and LDL cholesterol concentrations, with a rise in Lp(a) during a reduced SFA intake, this review also provides new data on the role of apolipoprotein(a) size polymorphism, a major genetic regulator of Lp(a) concentrations. Beyond an impact on Lp(a) concentrations, the extent to which diet might impact Lp(a)’s molecular and metabolic properties including its lipidomic composition remains unknown. Taken together, evidence shows the presence of a dietary modulation of Lp(a) beyond its genetic control and points to the need to better understand Lp(a)’s cardiovascular risk factor properties, including metabolomics/lipidomics characteristics. This also raises the issue whether diet should be a component of elevated Lp(a) management, and this needs to be addressed in future studies. Full article

Chronic inflammation plays a central role in the pathogenesis of lung diseases including asthma, long COVID, chronic obstructive pulmonary disease (COPD), and lung cancer. Lipopolysaccharide (LPS) is a potent inflammatory agent produced by Gram-negative bacteria and also found in cigarette smoke. Our earlier study revealed that the intranasal exposure of A/J mice to LPS for 7 days altered gene expression levels in alveolar Type II epithelial cells (AECIIs), which serve as precursors to lung adenocarcinoma and are also preferentially targeted by SARS-CoV-2. In the present work, we employed a comprehensive multi-omics approach to characterize changes in DNA methylation/hydroxymethylation, gene expression, and global protein abundances in the AECIIs of A/J mice following the sub-chronic exposure to LPS and after a 4-week recovery period. Exposure to LPS led to hypermethylation at regulatory elements within the genome such as enhancer regions and expression changes in genes known to play a role in lung cancer tumorigenesis. Changes in protein abundance were consistent with an inflammatory phenotype and also included tumor suppressor proteins. Integration of the multi-omics data resulted in a model where LPS-driven inflammation in AECIIs triggers epigenetic changes that, along with genetic mutations, may contribute to lung cancer development. Full article