Single Nucleotide Polymorphisms in Genes Encoding Toll-Like Receptors 7 and 8 and Their Association with Proviral Load of SRLVs in Goats of Polish Carpathian Breed

Recent advances in different interactions between toll-like receptors and hepatitis B infection: a review

Hepatitis B virus (HBV) B infections remain a primary global health concern. The immunopathology of the infection, specifically the interactions between HBV and the host immune system, remains somewhat unknown. It has been discovered that innate immune reactions are vital in eliminating HBV. Toll-like receptors (TLRs) are an essential category of proteins that detect pathogen-associated molecular patterns (PAMPs). They begin pathways of intracellular signals to stimulate pro-inflammatory and anti-inflammatory cytokines, thus forming adaptive immune reactions. HBV TLRs include TLR2, TLR3, TLR4, TLR7 and TLR9. Each TLR has its particular molecule to recognize; various TLRs impact HBV and play distinct roles in the pathogenesis of the disease. TLR gene polymorphisms may have an advantageous or disadvantageous efficacy on HBV infection, and some single nucleotide polymorphisms (SNPs) can influence the progression or prognosis of infection. Additionally, it has been discovered that similar SNPs in TLR genes might have varied effects on distinct populations due to stress, diet, and external physical variables. In addition, activation of TLR-interceded signaling pathways could suppress HBV replication and increase HBV-particular T-cell and B-cell reactions. By identifying these associated polymorphisms, we can efficiently advance the immune efficacy of vaccines. Additionally, this will enhance our capability to forecast the danger of HBV infection or the threat of dependent liver disease development via several TLR SNPs, thus playing a role in the inhibition, monitoring, and even treatment guidance for HBV infection. This review will show TLR polymorphisms, their influence on TLR signaling, and their associations with HBV diseases.

Individual genomic loci, transcript level, and biochemical profile of immune and antioxidant markers associated with genetically identified bacterial mastitis in Shami goats in Egypt

Background

Mastitis in goats is unquestionably a grave concern, with far-reaching implications for both animal well-being and productivity, while also presenting a potential threat to public health.

Aim

The study aimed to compare culture methods and multiplex PCR (m-PCR) in the detection of the most three common mastitis-causing pathogens (Staphylococcus aureus, Escherichia coli, and Streptococcus spp.) and investigate the gene expression, single nucleotide polymorphisms (SNPs), serum concentrations of immunological and antioxidant indicators linked to mastitis in Shami goats.

Methods

One hundred Shami do (50 Shami goats with clinical mastitis and 50 normal goats taken as control group). The culture methods and m-PCR analysis were used to find the bacteria in the milk samples. Blood samples were obtained to assess some hemato-biochemical parameters, detect SNPs, and determine the expression of certain immunological and antioxidant indicators in the genes.

Results

The culture method detected the pathogens causing mastitis in 90% of the milk samples, but m-PCR detected them in 100% of the milk samples. SNPs linked to mastitis resistance/susceptibility in examined does were detected through DNA sequencing of immunological and antioxidant indicators. The magnitude of gene expression varied significantly between the resistant and mastitis-affected groups. Significant (P ˂ 0.05) elevations were noticed in WBCs count, mainly neutsrophils count, serum levels of BHB, NEFA, triglycerides, LDL-C, AST, ALT, ALP, creatinine, total protein, globulin, Ca, K, GPx, MDA, acute phase proteins, and cytokines in mastitis affected does as compared to control. While RBCs count, PCV%, lymphocytes count, serum concentration of glucose, cholesterol, HDL-C, albumin, Na, Cl, P, GSH, SOD, and catalase significantly (P ˂ 0.05) diminished in mastitis affected does compared to healthy ones. APPs and pro-inflammatory cytokines scored high sensitivities and NPVs but TNF-α and serum amyloid A (SAA) had the highest percentages of increase.

Conclusion

The study confirmed that m-PCR is the most sensitive method for bacteria identification (S. aureus, E. coli, and Strept. spp.) while SNPs in antioxidant and immunological genes may be important genetic indicators for mastitis risk or resistance in Shami does. To establish an effective management plan and forecast the most sensitive risk time for illness onset, gene expression profiles of the tested genes may also be employed as proxy biomarkers. TNF-α and SAA may be precious indicators for the detection of caprine mastitis.

Antibody preparation and age-dependent distribution of TLR8 in Bactrian camel spleens

BACKGROUND

Toll-like receptor 8 (TLR8) can recognize specific pathogen-associated molecular patterns and exert multiple immunological functions through activation of signaling cascades. However, the precise distribution and age-related alterations of TLR8 in the spleens of Bactrian camels have not yet been investigated. This study aimed to prepare a rabbit anti-Bactrian camel TLR8 polyclonal antibody and elucidate the distribution of TLR8 in the spleens of Bactrian camels at different age groups. The methodology involved the construction of the pET-28a-TLR8 recombinant plasmid, followed by the expression of TLR8 recombinant protein via prokaryotic expression. Subsequently, rabbits were immunized with the purified protein to prepare the TLR8 polyclonal antibody. Finally, twelve Alashan Bactrian camels were categorized into four groups: young (1-2 years), pubertal (3-5 years), middle-aged (6-16 years) and old (17-20 years). These camels received intravenous sodium pentobarbital (20 mg/kg) anesthesia and were exsanguinated to collect spleen samples. Immunohistochemical techniques were employed to observe and analyze the distribution patterns and age-related changes of TLR8 in the spleen.

RESULTS

The results showed that the TLR8 recombinant protein was expressed in the form of inclusion body with a molecular weight of 52 kDa, and the optimal induction condition involved 0.3 mmol/L IPTG induction for 8 h. The prepared antibody yielded a titer of 1:32 000, and the antibody demonstrated specific binding to TLR8 recombinant protein. TLR8 positive cells exhibited a consistent distribution pattern in the spleen across different age groups of Bactrian camels, primarily scattered within the periarterial lymphatic sheath of the white pulp, marginal zone, and red pulp. The predominant cell type expressing TLR8 was macrophages, with expression also observed in neutrophils and dendritic cells. Statistical analysis revealed that there were significant differences in the distribution density of TLR8 positive cells among different spleen regions at the same age, with the red pulp, marginal zone, and white pulp showing a descending order (P<0.05). Age-related changes indicated that the distribution density in the marginal zone and red pulp exhibited a similar trend of initially increasing and subsequently decreasing from young to old camels. As camels age, there was a significant decrease in the distribution density across all spleen regions (P<0.05).

CONCLUSIONS

The results confirmed that this study successfully prepared a rabbit anti-Bactrian camel TLR8 polyclonal antibody with good specificity. TLR8 positive cells were predominantly located in the red pulp and marginal zone of the spleen, signifying their pivotal role in the innate immune response of the spleen. Aging was found to significantly reduce the density of TLR8 positive cells, while leaving their scattered distribution characteristics unaffected. These findings provide valuable support for further investigations into the immunomorphology and immunosenescence of the spleen in Bactrian camels.

The genetic variability of small-ruminant lentiviruses and its impact on tropism, the development of diagnostic tests and vaccines and the effectiveness of control programmes

Introduction

Maedi-visna virus and caprine arthritis encephalitis virus are two closely related lentiviruses which cause multisystemic, progressive and persistent infection in goats and sheep. Because these viruses frequently cross the species barrier, they are considered to be one genetic group called small-ruminant lentiviruses (SRLV). They have in vivo tropism mainly for monocytes and macrophages and organ tropism with unknown mechanisms. Typical clinical signs are pneumonia in sheep, arthritis in goats, and mastitis in both species. Infection with SRLV cannot currently be treated or prevented, and control programmes are the only approaches to avoiding its spread. These programmes rely mainly on annual serological testing and elimination of positive animals. However, the high genetic and antigenic variability of SRLV complicate their early and definitive diagnosis. The objective of this review is to summarise the current knowledge of SRLV genetic variation and its implications for tropism, the development of diagnostic tests and vaccines and the effectiveness of control and eradication programmes.

Material and Methods

Subject literature was selected from the PubMed and the Google Scholar databases.

Results

The high genetic diversity of SRLV affects the performance of diagnostic tools and therefore control programmes. For the early and definitive diagnosis of SRLV infection, a combination of serological and molecular tests is suggested. Testing by PCR can also be considered for sub-yearling animals. There are still significant gaps in our knowledge of the epidemiology, immunology and biology of SRLV and their impact on animal production and welfare.

Conclusion

This information may aid selection of the most effective SRLV spread reduction measures.

Genetic polymorphism in European and African sheep breeds reared in Hungary based on 48 SNPs associated with resistance to gastrointestinal parasite infection using KASP-PCR technique

This pilot study used an alternative and economically efficient technique, the Kompetitive Allele-Specific Polymerase Chain Reaction (KASP-PCR) to examine 48 SNPs from 11 parasite-resistance genes found on 8 chromosomes in 110 animals from five sheep breeds reared in Hungary; Hungarian Tsigai, White Dorper, Dorper, Ile de France, and Hungarian Merino. Allele and genotype frequencies, fixation index, observed heterozygosity, expected heterozygosity, F statistic, and their relationship with the Hardy-Weinberg equilibrium (WHE) and the polymorphic information content (PIC) were determined, followed by principal component analysis (PCA). As much as 32 SNPs out of the 48 initially studied were successfully genotyped. A total of 9 SNPs, 4 SNPs in TLR5, 1 SNP in TLR8, and 4 SNPs in TLR2 genes, were polymorphic. The variable genotype and allele frequency of the TLRs gene indicated genetic variability among the studied sheep breeds, with the Hungarian Merino exhibiting the most polymorphisms, while Dorper was the population with the most SNPs departing from the HWE. According to the PIC value, the rs430457884-TLR2, rs55631273-TLR2, and rs416833129-TLR5 were found to be informative in detecting polymorphisms among individuals within the populations, whereas the rs429546187-TLR5 and rs424975389-TLR5 were found to have a significant influence in clustering the population studied. This study reported a moderate level of genetic variability and that a low to moderate within-breed diversity was maintained in the studied populations.

Molecular Characterization of Small Ruminant Lentiviruses Isolated from Polish Goats with Arthritis

Previous studies revealed that the small ruminant lentivirus (SRLV) population in Poland is highly heterogeneous. All SRLVs detected from Polish sheep and goats so far have belonged to subtypes B1, B2, A1, A5, A12, A13, A16, A17, A18, A23 and A24. However, all characterized strains originated from asymptomatic animals. This is the first study that characterizes the molecular properties of SRLVs isolated from different organs of six arthritic goats. Segments from three genomic regions (gag, LTR and env) were analyzed. In addition, we quantified the SRLV proviral load in the blood and different organs and examined its association with different degrees of histopathological lesions. All sequences obtained from the goats involved in this study were homogeneous, showing an average degree of variability of 4.8%, 3.7% and 8.8% for gag, LTR and env, respectively. Phylogenetic analysis revealed that the sequences from the analyzed goats were clustered within SRLVs group A and formed a new subtype within this group, tentatively named A27. The histopathological examination of the lung, mammary gland, synovial membranes of joints and brain of the analyzed goats revealed evidence of inflammatory processes associated with SRLV infection, which was confirmed by positive immunohistochemistry assays. No significant correlation was observed between histological features and alterations in the sequences from different tissues. No tissue-specific signature pattern was identified. It was shown that animals with a higher proviral load showed more lesion severity in various SRLV-affected tissues, indicating a positive association between these two parameters. Our results also revealed differences in the SRLV load between animals even though the sequences derived from all of the goats were closely related, suggesting that host factors may restrict and control viral replication. This study provides new information about SRLV variants isolated from arthritic goats; however, more studies, including the isolation and characterization of biological properties of these viruses, should be performed to evaluate their pathogenic potential.

Transcriptome Analysis for Genes Associated with Small Ruminant Lentiviruses Infection in Goats of Carpathian Breed

Small ruminant lentiviruses (SRLV) are economically important viral pathogens of sheep and goats. SRLV infection may interfere in the innate and adaptive immunity of the host, and genes associated with resistance or susceptibility to infection with SRLV have not been fully recognized. The presence of animals with relatively high and low proviral load suggests that some host factors are involved in the control of virus replication. To better understand the role of the genes involved in the host response to SRLV infection, RNA sequencing (RNA-seq) method was used to compare whole gene expression profiles in goats carrying both a high (HPL) and low (LPL) proviral load of SRLV and uninfected animals. Data enabled the identification of 1130 significant differentially expressed genes (DEGs) between control and LPL groups: 411 between control and HPL groups and 1434 DEGs between HPL and LPL groups. DEGs detected between the control group and groups with a proviral load were found to be significantly enriched in several gene ontology (GO) terms, including an integral component of membrane, extracellular region, response to growth factor, inflammatory and innate immune response, transmembrane signaling receptor activity, myeloid differentiation primary response gene 88 (MyD88)-dependent toll-like receptor signaling pathway as well as regulation of cytokine secretion. Our results also demonstrated significant deregulation of selected pathways in response to viral infection. The presence of SRLV proviral load in blood resulted in the modification of gene expression belonging to the toll-like receptor signaling pathway, the tumor necrosis factor (TNF) signaling pathway, the cytokine-cytokine receptor interaction, the phagosome, the Ras signaling pathway, the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) (PI3K-Akt) signaling pathway and rheumatoid arthritis. It is worth mentioning that the most predominant in all pathways were genes represented by toll-like receptors, tubulins, growth factors as well as interferon gamma receptors. DEGs detected between LPL and HPL groups were found to have significantly enriched regulation of signaling receptor activity, the response to toxic substances, nicotinamide adenine dinucleotide (NADH) dehydrogenase complex assembly, cytokine production, vesicle, and vacuole organization. In turn, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway tool classified DEGs that enrich molecular processes such as B and T-cell receptor signaling pathways, natural killer cell-mediated cytotoxicity, Fc gamma R-mediated phagocytosis, toll-like receptor signaling pathways, TNF, mammalian target of rapamycin (mTOR) signaling and forkhead box O (Foxo) signaling pathways, etc. Our data indicate that changes in SRLV proviral load induced altered expression of genes related to different biological processes such as immune response, inflammation, cell locomotion, and cytokine production. These findings provide significant insights into defense mechanisms against SRLV infection. Furthermore, these data can be useful to develop strategies against SRLV infection by selection of animals with reduced SRLV proviral concentration that may lead to a reduction in the spread of the virus.