Transcriptome analysis of gene expression profiling of infected macrophages between Brucella suis 1330 and live attenuated vaccine strain S2 displays mechanistic implication for regulation of virulence

Investigation of the Seroprevalence of Brucella Antibodies and Characterization of Field Strains in Immunized Dairy Cows by B. abortus A19

(1) Background: One method of eradicating brucellosis is to cull cattle that test positive for antibodies 12 months after being vaccinated with the 19-strain vaccine. Variations in immunization regimens and feeding practices may contribute to differences in the rate of persistent antibodies. We conducted this study to investigate the real positive rate of Brucella antibody in field strains of Brucella spp. after immunization over 12 months in dairy cows. This research aims to provide data to support the development of strategies for preventing, controlling, and eradicating brucellosis. (2) Method: We employed the baseline sampling method to collect samples from cows immunized with the A19 vaccine for over 12 months in Lingwu City from 2021 to 2023. Serological detection was conducted using the RBPT method. An established PCR method that could distinguish between 19 and non-19 strains of Brucella was utilized to investigate the field strains of Brucella on 10 dairy farms based on six samples mixed into one using the Mathematical Expectation strategy. (3) Results: We analyzed the rates of individual seropositivity and herd seropositive rates in dairy cattle in Lingwu City from 2021 to 2023 and revealed that antibodies induced by the Brucella abortus strain A19 vaccine persist in dairy herds for more than 12 months. We established a PCR method for identifying both Brucella A19 and non-A19 strains, resulting in the detection of 10 field strains of Brucella abortus from 1537 dairy cows. By employing a Mathematical Expectation strategy, we completed testing of 1537 samples after conducting only 306 tests, thereby reducing the workload by 80.1%. (4) Conclusions: There was a certain proportion of cows with a persistent antibody titer, but there was no evidence that all of these cattle were naturally infected with Brucella. The established PCR method for distinguishing between Brucella abortus strain 19 and non-19 strains can be specifically utilized for detecting natural Brucella infection in immunized cattle. We propose that relying solely on the detection of antibodies in cattle immunized with the A19 vaccine more than 12 months previously should not be solely relied upon as a diagnostic basis for brucellosis, and it is essential to complement this approach with PCR analysis to specifically identify field Brucella spp. Brucella abortus was the predominant strain identified in the field during this study. Detection based on the Mathematical Expectation strategy can significantly enhance detection efficiency.

Transcriptome and the gut microbiome analysis of the impacts of Brucella abortus oral infection in BALB/c mice

Brucellosis is a zoonotic infectious disease caused by Brucella spp, which could cause serious economic losses to animal husbandry and threaten human public health. Ingestion of contaminated animal products is a common way to acquire Brucella infection in humans, while research on effect of oral Brucella infection on host gut microbiota and the gene expression in intestinal tissues is limited. In the present study, 16S rRNA sequencing and RNA sequencing were conducted to explore gut microbiota and expression profiles of mRNAs in the colon of BALB/c mice, which were infected by Brucella abortus 2308. The fecal samples were collected at 7 and 28 days post infection to observe changes in the gut microbiota during Brucella infection. In the alpha diversity analysis, significantly increased Chao 1 index was observed at 28 days after Brucella infection. The Bray-Curtis distancebased principal coordinate analysis indicated that the WT group showed a separation from the Brucella infection groups. In addition, analysis of composition of microbes revealed that Prevotellaceae_NK3B31_group were more abundant in 1 week and 4 week infection groups, while Turicibacter was only more abundant in 4 week infection group. Based on the RNA-seq assay, a total of 45 differentially expressed genes were detected between Brucella abortus infection group and control group. Furthermore, KEGG pathway enrichment analysis showed that protein processing in endoplasmic reticulum, Legionellosis, Spliceosome, Hippo signaling pathway and Influenza A were significantly enriched in response to Brucella abortus infection. Our finding will help to improve the knowledge of the mechanisms underlying Brucella infection and may provide novel targets for future treatment of this pathogen infection.

Clearance of bacteria from lymph nodes in sheep immunized with Brucella suis S2 vaccine is associated with M1 macrophage activation

Ovine brucellosis is a global zoonotic disease of sheep caused by Brucella melitensis, which inflicts a significant burden on human and animal health. Brucella suis strain S2 (B. suis S2) is a smooth live attenuated vaccine for the prevention of ovine brucellosis in China. However, no previous studies have assessed the immunogenicity of B. suis S2 vaccine after oral immunization in sheep. Here, we attempted to evaluate the ovine immune response over the course of B. suis S2 immunization and to identify in vivo predictors for vaccine development. Body temperature, serum Brucella antibodies, serum cytokines (IL-12p70 and interferon [IFN]-γ), and bacterial load in the mandibular lymph nodes (LN), superficial cervical LN, superficial inguinal LN, and spleen were investigated to determine the safety and efficacy of the vaccine. The abnormal body temperature of sheep occurred within 8 days post-infection (dpi). Brucella suis S2 persisted for a short time (< 21 dpi) in the mandibular LN. The highest level of IL-12p70 was observed at 9 dpi, whereas serum IFN-γ levels peaked at 12 dpi. Transcriptome analysis and quantitative reverse transcription PCR were performed to determine gene expression profiles in the mandibular LN of sheep. Antigen processing and presentation pathway was the dominant pathway related to the dataset. Our studies suggest that the immune response in ovine LN resembled type 1 immunity with the secretion of IL-12p70 and IFN-γ after B.suis S2 immunization and the vaccine may eliminate Brucella via stimulation of M1 macrophages through the course of Th cells.

Differentially expressed long noncoding RNAs in RAW264.7 macrophages during Brucella infection and functional analysis on the bacterial intracellular replication

Long noncoding RNAs (lncRNAs) are a group of functional RNA molecules without protein-coding potential and play vital roles in majority of biological processes. To date, the expression profiles of lncRNAs and their influence on Brucella replication in RAW264.7 cells are poorly understood. In this study, we performed high-throughput transcriptome analysis to investigate the differentially expressed lncRNAs associated with Brucella abortus S2308 infection. Of these, 8, 6, 130 and 94 cellular lncRNAs were differentially expressed at 4, 8, 24 and 48 h post-infection, respectively. Moreover, 1918 protein-coding genes are predicted as potential cis target genes of differentially expressed lncRNAs by searching protein-coding genes located at upstream and downstream of lncRNA loci on the chromosome DNA of Mus musculus. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that majority of lncRNA target genes were associated with B. abortus infection. Fourteen lncRNAs from transcriptome data were selected for qRT-PCR verification, confirming 13 were differentially expressed. Animal experiments revealed three were differentially expressed in vivo by qRT-PCR analysis. Furthermore, knockdown of LNC_000428 by CRISPR/dCas9 inhibition or Locked Nucleic Acids transfection downregulated Tnfrsf8 expression at mRNA level and increased Brucella intracellular replication. Thus, we provide a novel evidence that lncRNAs induced by Brucella-infection function on Brucella intracellular replication.

Brucella melitensis outer membrane protein 25 interacts with ferritin heavy polypeptide 1 in human trophoblast cells

Outer membrane protein 25 (OMP25) is involved in Brucella virulence and serves an important role in Brucella pathogenesis during infection. However, the protein interacting with OMP25 in host cells remains to be elucidated. The present study constructed a cDNA library from Brucella melitensis 16M‑infected human placenta trophoblastic cells (HPT‑8) and identified and confirmed the interaction between Brucella OMP25 and ferritin heavy polypeptide 1 (FTH1) of HPT‑8 using yeast two‑hybrid and co‑immunoprecipitation technologies. The expression of Toll‑like receptor (TLR)4, myeloid differentiation primary response protein MyD88 (MyD88) mRNA and inflammatory factors was detected by RNA interference. The results showed that OMP25 interacted with FTH1. Subsequently, TLR4 and MyD88 mRNA expression levels and inflammatory factors, such as nitric oxide, lactate dehydrogenase and TNF‑α, significantly increased after inserting OMP25 into the HPT‑8 cells. Notably, a low dose of OMP25 resulted in immunological protection, whereas high dose of OMP25 resulted in a cytotoxic effect on the HPT‑8 cells. It is suggested that OMP25 and FTH1 serve important roles in intracellular parasitism of Brucella and inhibition of expression.

Downregulation of Three Novel miRNAs in the Lymph Nodes of Sheep Immunized With the Brucella suis Strain 2 Vaccine

Ovine and caprine brucellosis, both caused by Brucella melitensis, lead to substantial economic losses in the animal industry and health problems in human populations. Brucella suis strain 2 (B.suis S2), as a live attenuated vaccine, is used extensively in China to prevent brucellosis. It has been proven that microRNA (miRNAs) are involved in the immunopathogenesis of brucellosis; however, the miRNA-driven mechanism of immune response to B.suis S2 in vivo remains unknown. To determine which new miRNAs are involved in the host immune response to B.suis S2 and elucidate the function of these miRNAs, we performed a comprehensive analysis of miRNA expression profiles in sheep immunized with B.suis S2 using the high-throughput sequencing approach. The submandibular lymphatic nodes from sheep seropositive for Brucella were collected at 7, 14, 21, 30, 60 and 90 days post-immunization. MiRNA sequencing analysis revealed that 282 differentially expressed miRNAs (|log₂ fold-change |>0.5 and p < 0.05) were significantly enriched in the immune pathways, including the NF-kappa B signaling pathway, B cell receptor signaling pathway, p53 signaling pathway and complement and coagulation cascades. Increasing the threshold to |log₂ fold change|>1 and p < 0.01 revealed 48 differentially expressed miRNAs, 31 of which were novel miRNAs. Thirteen of these novel miRNAs, which were differentially expressed for at least two time points, were detected via RT-qPCR assays. The novel_229, novel_609, novel_973 and oar-miR-181a assessed by RT-qPCR were detectable and consistent with the expression patterns obtained by miRNA sequencing. Functional analyses of these miRNAs demonstrated that their target genes participated in the immune response pathways, including the innate and adaptive immunity pathways. The immune-related target genes of novel_229 included ENSOARG00000000649 and TMED1, as well as LCN2, PDPK1 and LPO were novel_609 target genes. The immune-related target genes of novel_973 included C6orf58, SPPL3, BPIFB1, ENSOARG00000021083, MPTX1, CCL28, FGB, IDO1, OLR1 and ENSOARG00000020393. The immune-related target genes of oar-miR-181a included ENSOARG00000002722, ARHGEF2, MFAP4 and DOK2. These results will deepen our understanding of the host miRNA-driven defense mechanism in sheep immunized with B.suis S2 vaccine, and provide the valuable information for optimizing vaccines and developing molecular diagnostic targets.

Over-expression of SRD5A3 and its prognostic significance in breast cancer

Objective

The study aimed to compare the Steroid 5 alpha-reductase 3 (SRD5A3) expression levels in breast cancer (BC) and normal tissues, to investigate the prognostic value of SRD5A3 mRNA expression in BC patients and to identify the SRD5A3-related signaling pathways using bioinformatics approaches.

Methods

We evaluated the expression levels of SRD5A3 and survival data in BC patients using different bioinformatic databases. Further, Cox regression analysis was conducted to predict the independent prognostic factors for BC. Moreover, the association of SRD5A3 with clinicopathological factors was measured through LinkedOmics database. And the potential role of SRD5A3 was determined by Gene Ontology and KEGG pathway enrichment analysis. Finally, protein network of SRD5A3 was constructed and genetic alterations were analyzed.

Results

Bioinformatic data indicated that both mRNA and protein expression levels of SRD5A3 were higher in BC group than those in the normal group (P < 0.05). Besides, BC patients with higher SRD5A3 mRNA expression levels had a lower overall survival (all P < 0.05). Cox regression analysis further demonstrated the independent prognostic value of SRD5A3 in BC (P = 0.015). SRD5A3 mRNA expression was significantly associated with N stage (P < 0.001), age (P < 0.05), and histologic subtype (P < 0.001) but had no significant relationship with other clinical characteristics (all P > 0.05). Moreover, the functional enrichment analysis revealed that the SRD5A3 was involved in metabolism-related pathways (all P < 0.05).

Conclusions

SRD5A3 was highly expressed in BC tissues and high SRD5A3 expression was related to poorer prognosis. SRD5A3 serves as an oncogene and might function as a potential biomarker for prognosis and a therapeutic target for BC.

Safety and Transcriptome Analysis of Live Attenuated Brucella Vaccine Strain S2 on Non-pregnant Cynomolgus Monkeys Without Abortive Effect on Pregnant Cynomolgus Monkeys

Brucellosis, caused by Brucella spp., is an important zoonotic disease leading to enormous economic losses in livestock, posing a great threat to public health worldwide. The live attenuated Brucella suis (B. suis) strain S2, a safe and effective vaccine, is widely used in animals in China. However, S2 vaccination in animals may raise debates and concerns in terms of safety to primates, particularly humans. In this study, we used cynomolgus monkey as an animal model to evaluate the safety of the S2 vaccine strain on primates. In addition, we performed transcriptome analysis to determine gene expression profiling on cynomolgus monkeys immunized with the S2 vaccine. Our results suggested that the S2 vaccine was safe for cynomolgus monkeys. The transcriptome analysis identified 663 differentially expressed genes (DEGs), of which 348 were significantly upregulated and 315 were remarkably downregulated. The Gene Ontology (GO) classification and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that these DEGs were involved in various biological processes (BPs), including the chemokine signaling pathway, actin cytoskeleton regulation, the defense response, immune system processing, and the type-I interferon signaling pathway. The molecular functions of the DEGs were mainly comprised of 2'-5'-oligoadenylate synthetase activity, double-stranded RNA binding, and actin-binding. Moreover, the cellular components of these DEGs included integrin complex, myosin II complex, and blood microparticle. Our findings alleviate the concerns over the safety of the S2 vaccine on primates and provide a genetic basis for the response from a mammalian host following vaccination with the S2 vaccine.

Genomic insights into Brucella

Brucellosis is a zoonotic disease caused by certain species of Brucella. Each species has its preferred host animal, though it can infect other animals too. For a longer period, only six classical species were recognized in the genus Brucella. No vaccine is available for human brucellosis. Therefore, human brucellosis can be controlled only by controlling brucellosis in animals. The genus is now expanding with the newly isolated atypical strains from various animals, including marine mammals. Presently, 12 species of Brucella have been recognized. The first genome of Brucella was released in 2002, and today, we have more than 1500 genomes of Brucella spp. isolated worldwide. Multiple genome sequences are available for the major zoonotic species, B. abortus, B. melitensis, and B. suis. The Brucella genome has two chromosomes with the approximate sizes of 2.1 and 1.2 Mbp. The genome of Brucella is highly conserved across all the species at the nucleotide level. One of the unanswered questions is what makes host preference in different species of Brucella. Here, I summarize the recent advancements in the Brucella genomics research.

Chemokine receptor 4 (CXCR4) blockade enhances resistance to bacterial internalization in RAW264.7 cells and AMD3100, a CXCR4 antagonist, attenuates susceptibility to Brucella abortus 544 infection in a murine model

We investigated the involvement of chemokine receptor type 4 (CXCR4) signaling on the outcome of Brucella (B.) abortus 544 infection in murine macrophages and in a mouse model. CXCR4 manipulation were first evaluated for Brucella invasion and intracellular survival efficiency, mitogen-activated protein kinases (ERK1/2, JNK, p38α) activation and generation of nitric oxide (NO), and then in the splenic bacterial proliferation and cytokine production in BALB/c mice. CXCR4 blockade is involved in the successful control of Brucella invasion, reduction of ERK1/2 phosphorylation and inhibition of nitric oxide release from macrophages. Furthermore, using a reported CXCR4-specific antagonist AMD3100 resulted in splenomegaly but attenuated Brucella proliferation in these organs with elevated serum levels of MCP-1, TNF and IL-12. These findings provide insights on the contribution of CXCR4 signaling in the phagocytic pathway and immune modulation during B. abortus infection.

Hydrogen sulfide exposure induces jejunum injury via CYP450s/ROS pathway in broilers

Hydrogen sulfide (H₂S) is generally recognized as a highly poisonous environmental and industrial pollutant. Previous toxicological studies of H₂S are mainly focused on the nervous and cardiovascular system. There are few reports on the H₂S toxicity effects on jejunum to our knowledge. Our study examined the morphological changes and antioxidant functions of broiler jejunum after the 42-day exposure to H₂S. Effects of H₂S on morphological damage and immune function in the broiler jejunum were analyzed from the perspective of CYP450s and oxidative stress via transcriptomics and quantitative real-time PCR (qRT-PCR). It was found that the activities of GPx, CAT, SOD, and T-AOC and the level of GSH were observably decreased (P < 0.05), while the contents of MDA and H₂O₂ were remarkably increased (P < 0.05) in the jejunums of broilers exposed to H₂S, which undergone a process of oxidative stress, and typical inflammatory changes and apoptosis could be observed. Transcriptional profiling results showed that 208 genes were significantly up-regulated while 295 genes were remarkably down-regulated in H₂S group. The expression of CYP450s, inflammation and apoptosis-related genes were also significantly increased. In conclusion, H₂S led to the redox homeostasis disorder through CYP450s differential expression in broiler jejunum. The jejunal inflammatory response, apoptosis along with the immune dysfunction were subsequently observed, which eventually caused jejunal morphology and functional damage. The present study further enriches and perfects the mechanism theory of H₂S toxicity on broilers, which may be valuable for the risk assessment of H₂S and human health protection.

An Overview of Brucellosis in Cattle and Humans, and its Serological and Molecular Diagnosis in Control Strategies

Brucellosis is one of the most common contagious and communicable zoonotic diseases with high rates of morbidity and lifetime sterility. There has been a momentous increase over the recent years in intra/interspecific infection rates, due to poor management and limited resources, especially in developing countries. Abortion in the last trimester is a predominant sign, followed by reduced milk yield and high temperature in cattle, while in humans it is characterized by undulant fever, general malaise, and arthritis. While the clinical picture of brucellosis in humans and cattle is not clear and often misleading with the classical serological diagnosis, efforts have been made to overcome the limitations of current serological assays through the development of PCR-based diagnosis. Due to its complex nature, brucellosis remains a serious threat to public health and livestock in developing countries. In this review, we summarized the recent literature, significant advancements, and challenges in the treatment and vaccination against brucellosis, with a special focus on developing countries.