Bactericidal/permeability-increasing protein originates in both the testis and the epididymis and localizes in mouse spermatozoa

Genes and Pathways Underpinning Klinefelter Syndrome at Bulk and Single-Cell Levels

Klinefelter syndrome (KS) is the most frequent genetic anomaly in infertile men. Given its unclear mechanism, we aim to investigate critical genes and pathways in the pathogenesis of KS based on three bulk and one single-cell transcriptome data sets from Gene Expression Omnibus. We merged two data sets (GSE42331 and GSE47584) with human KS whole blood samples. When comparing the control and KS samples, five hub genes, including defensin alpha 4 (DEFA4), bactericidal permeability increasing protein (BPI), myeloperoxidase (MPO), intelectin 1 (ITLN1), and Xg Glycoprotein (XG), were identified. Besides, infiltrated degree of certain immune cells such as CD56bright NK cell were positively associated with the expression of ITLN1 and XG. Kyoto Encyclopedia of Genes and Genomes analysis identified upregulated phosphatidylinositol 3-kinase (PI3K)/AKT pathway in KS. Gene set enrichment analysis followed by gene set variation analysis confirmed the upregulation of G2M checkpoint and heme metabolism in KS. Thereafter, the GSE200680 data set was used for external validation of the expression variation of hub genes from healthy to KS testicular samples, and each hub gene yielded excellent discriminatory capability for KS without exception. At the single-cell level, the GSE136353 data set was utilized to evaluate intercellular communication between different cell types in KS patient, and strong correlations were detected between macrophages/ dendritic cells/ NK cells and the other cell types. Collectively, we provided hub genes, pathways, immune cell infiltration degree, and cell-cell communication in KS, warranting novel insights into the pathogenesis of this disease.

Comparing morphological and secretory aspects of cephalic glands among the New World coral snakes brings novel insights on their biological roles

Oral and other cephalic glands have been surveyed by several studies with distinct purposes. Despite the wide diversity and medical relevance of the New World coral snakes, studies focusing on understanding the biological roles of the glands within this group are still scarce. Specifically, the venom glands of some coral snakes were previously investigated but all other cephalic glands remain uncharacterized. In this sense, performing morphological and molecular analysis of these glands may help better understand their biological role. Here, we studied the morphology of the venom, infralabial, rictal, and harderian glands of thirteen species of Micrurus and Micruroides euryxanthus. We also performed a molecular characterization of these glands from selected species of Micrurus using transcriptomic and proteomic approaches. We described substantial morphological variation in the cephalic glands of New World coral snakes and structural evidence for protein-secreting cells in the inferior rictal glands. Our molecular analysis revealed that the venom glands, as expected, are majorly devoted to toxin production, however, the infralabial and inferior rictal glands also expressed some toxin genes at low to medium levels, despite the marked morphological differences. On the other hand, the harderian glands were dominated by the expression of lipocalins, but do not produce toxins. Our integrative analysis, including the prediction of biological processes and pathways, helped decipher some important traits of cephalic glands and better understand their biology.

Identification and Functional Analysis of ToBPI1/LBP and ToBPI2/LBP in Anti-Bacterial Infection of Trachinotus ovatus

Bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) are a group of antibacterial proteins that play an important role in the host's innate immune defense against pathogen infection. In this study, two BPI/LBPs, named ToBPI1/LBP (1434 bp in length, 478 amino acids) and ToBPI2/LBP (1422 bp in length, 474 amino acids), were identified from the golden pompano. ToBPI1/LBP and ToBPI2/LBP were significantly expressed in immune-related tissues after being challenged with Streptococcus agalactiae and Vibrio alginolyticus. The two BPI/LBPs showed significant antibacterial activity against Gram-negative Escherichia coli and Gram-positive S. agalactiae and Streptococcus iniae. In contrast, the antibacterial activity against Staphylococcus aureus, Corynebacterium glutamicum, Vibrio parahaemolyticus, V. alginolyticus and Vibrio harveyi was low and decreased with time. The membrane permeability of bacteria treated with recombinant ToBPI1/LBP and ToBPI2/LBP was significantly enhanced. These results suggest that ToBPI1/LBP and ToBPI2/LBP may play important immunological roles in the immune response of the golden pompano to bacteria. This study will provide basic information and new insights into the immune response mechanism of the golden pompano to bacteria and the function of BPI/LBP.

Gene Expression in Embryos From Norwegian Red Bulls With High or Low Non Return Rate: An RNA-Seq Study of in vivo-Produced Single Embryos

During the last decade, paternal effects on embryo development have been found to have greater importance than previously believed. In domestic cattle, embryo mortality is an issue of concern, causing huge economical losses for the dairy cattle industry. In attempts to reveal the paternal influence on embryo death, recent approaches have used transcriptome profiling of the embryo to find genes and pathways affected by different phenotypes in the bull. For practical and economic reasons, most such studies have used in vitro produced embryos. The aim of the present study was to investigate the differences in the global transcriptome of in vivo produced embryos, derived from sires with either high or low field fertility measured as the non-return rate (NRR) on day 56 after first AI of the inseminated cows. Superovulated heifers (n = 14) in the age span of 12–15 months were artificially inseminated with semen from either high fertility (n = 6) or low fertility (n = 6) bulls. On day seven after insemination, embryos were retrieved through uterine flushing. Embryos with first grade quality and IETS stage 5 (early blastocyst), 6 (blastocyst) or 7 (expanded blastocyst) were selected for further processing. In total, RNA extracted from 24 embryos was sequenced using Illumina sequencing, followed by differential expression analysis and gene set enrichment analysis. We found 62 genes differentially expressed between the two groups (adj.p-value<0.05), of which several genes and their linked pathways could explain the different developmental capacity. Transcripts highly expressed in the embryos from low fertility bulls were related to sterol metabolism and terpenoid backbone synthesis, while transcripts highly expressed in the high fertility embryos were linked to anti-apoptosis and the regulation of cytokine signaling. The leukocyte transendothelial migration and insulin signaling pathways were associated with enrichments in both groups. We also found some highly expressed transcripts in both groups which can be considered as new candidates in the regulation of embryo development. The present study is an important step in defining the paternal influence in embryonic development. Our results suggest that the sire’s genetic contribution affects several important processes linked to pre-and peri implantation regulation in the developing embryo.

Bactericidal/Permeability-Increasing Protein Improves Cognitive Impairment in Diabetic Mice via Blockade of the LPS-LBP-TLR4 Signaling Pathway

Emerging evidence suggests that the bactericidal/permeability-increasing protein (BPI) is involved in the process of cognitive impairment in diabetes. However, its underlying mechanism remains elusive. In this study, we found that BPI affects cognitive impairment due to diabetes through the lipopolysaccharide (LPS)-lipopolysacharide-binding protein (LBP)-toll-like receptor 4 (TLR4) signaling pathway. We examined the expression of BPI, LPS, LBP, CD14, and TLR4 in established mouse models of diabetes induced by high-fat diet (HFD) in combination with streptozotocin (STZ). Diabetic mice were then injected with adeno-associated-virus carrying BPI overexpression vectors and LPS. Fasting blood glucose, plasma insulin, and serum levels of inflammatory factors were examined. Then, glucose tolerance and, insulin resistance tests were used to measure systemic insulin sensitivity. Next, hippocampal tissue injury and cell apoptosis were examined by hematoxylin-eosin (HE) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining. Diabetic mice displayed increased LPS expression and activation of the LPS-CD14-TLR4 signaling pathway. HFD mice following LPS treatment showed significantly increased serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6, and expressions of Bcl-2-associated X protein (Bax) and Aβ but decreased expression of Bcl-2 in hippocampal tissues, as well as enhanced fasting blood glucose, plasma insulin, glucose tolerance, insulin tolerance, cell apoptosis, aggravated hippocampal tissue injury and, ultimately, cognitive impairment. However, overexpression of BPI was able to rescue the aforementioned phenotypes driven by LPS treatment. Taken together, BPI could potentially provide relief from cognitive impairment in diabetic mice by disrupting the LPS-LBP-TLR4 signaling pathway, underscoring a possible alternative therapeutic strategy against the cognitive impairment associated with diabetes.

Serum BPI as a novel biomarker in asthma

Background

Neutrophils, eosinophils and inflammatory cells contribute to asthmatic inflammation. The anti-bactericidal/permeability-increasing protein (BPI), produced by neutrophils, peripheral blood monocytes or epithelial cells, can neutralize lipopolysaccharide activity and enhance phagocytosis regulation function. This study aimed to assess the clinical significance of BPI in asthmatic patients.

Methods

We recruited 18 controlled asthma, 39 uncontrolled asthma and 35 healthy controls individuals. Clinical characteristics (age, gender, allergy history, body mass index (BMI) and smoking history), clinical indicators [whole blood count, forced expiratory volume in one second as percentage of predicted volume (FEV1% predicted), IgE level, high sensitivity C-reactive protein (hs-CRP) and fractional expiratory nitric oxide (FeNO)] and serum BPI levels were measured to compare among each group. We then evaluated the correlation between BPI, clinical characteristics and clinical indicators. Finally, linear regression analysis was performed to exclude the influence of other factors and to find the independent influencing factors of BPI.

Results

Our results showed that the serum BPI levels increased by twofold in the controlled asthma group (12.83 ± 6.04 ng/mL) and threefold in the uncontrolled asthma group (18.10 ± 13.48 ng/mL), compared to the healthy control group (6.00 ± 2.58 ng/mL) (p < 0.001). We further found that serum BPI levels were positively correlated with the hs-CRP (p = 0.002). There was no significant association among BPI, age, gender, BMI, allergy, blood eosinophils, blood neutrophils, IgE, FeNO or FEV1% predicted.

Conclusion

BPI levels were increased in asthma and positively correlated with hs-CRP. BPI as a potential asthma biomarker that still needs further research.

Effects of increased scrotal temperature on semen quality and seminal plasma proteins in Brahman bulls

Environmental temperature has effects on sperm quality with differences in susceptibility between cattle subspecies and breeds, but very little is known about the seminal plasma protein (SPP) changes resulting from testicular heat stress. Scrotal insulation (SI) for 48 hr was applied to Brahman (Bos indicus) bulls. Semen was collected at 3-day intervals from before, until 74 days post-SI. The changes in sperm morphology and motility following SI were comparable to previously reported and differences were detected in measures of sperm chromatin conformation as early as 8 days post-SI. New proteins spots, in the SPP two-dimensional (2-D) gels, were apparent when comparing pre-SI with 74 days post-SI, and SPP identified as associated with mechanisms of cellular repair and protection. Similar trends between 2-D gel and Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS) data was observed, with SWATH-MS able to quantify individual SPP that otherwise were not resolved on 2-D gel. The SPP assessment at peak sperm damage (21-24 days) showed a significant difference in 29 SPP (adjusted p < .05), and identified six proteins with change in abundance in the SI group. In conclusion both spermatozoa and SPP composition of bulls are susceptible to temperature change incurred by SI, and SPP markers for testicular heat insults may be detected.

Molecular identification and function analysis of bactericidal permeability-increasing protein/LPS-binding protein 1 (BPI/LBP1) from turbot (Scophthalmus maximus)

Bactericidal permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) play important roles in host antimicrobial defense. In the present study, we identified one isoform of BPI/LBP gene from turbot (Scophthalmus maximus), designated as SmBPI/LBP1. The full-length cDNA sequence of SmBPI/LBP1 was 1826 bp, which encoding one secreted protein with 480 amino acid residues. Structurally, the SmBPI/LBP1 showed high similarity to its homologs from other vertebrates or invertebrates, which all contained a signal peptide, a BPI/LBP/CETP N-terminal with a LPS-binding domain, and a BPI/LBP/CETP C-terminal domain. The deduced amino acid sequences of SmBPI/LBP1 shared significant similarity to BPI/LBP of Seriola lalandi dorsalis (71%) and Paralichthys olivaceus (69%). Phylogentic analysis further supported that SmBPI/LBP1 act as a new member of vertebrate BPI/LBP family. SmBPI/LBP1 was ubiquitously expressed in all tested tissues, with the highest expression level in spleen tissue. The mRNA expression of SmBPI/LBP1 in spleen and kidney were significantly up-regulated after Vibrio vulnificus challenge. Finally, the recombinant SmBPI/LBP1 showed high affinity to lipopolysaccharide, followed by peptidoglycan and lipoteichoic acid, which is the ubiquitous component of Gram-negative or Gram-positive bacteria. These results indicated that SmBPI/LBP1 probably played important roles in immune response against bacteria infection.

The Harderian gland transcriptomes of Caraiba andreae, Cubophis cantherigerus and Tretanorhinus variabilis, three colubroid snakes from Cuba

The Harderian gland is a cephalic structure, widely distributed among vertebrates. In snakes, the Harderian gland is anatomically connected to the vomeronasal organ via the nasolacrimal duct, and in some species can be larger than the eyes. The function of the Harderian gland remains elusive, but it has been proposed to play a role in the production of saliva, pheromones, thermoregulatory lipids and growth factors, among others. Here, we have profiled the transcriptomes of the Harderian glands of three non-front-fanged colubroid snakes from Cuba: Caraiba andreae (Cuban Lesser Racer); Cubophis cantherigerus (Cuban Racer); and Tretanorhinus variabilis (Caribbean Water Snake), using Illumina HiSeq2000 100 bp paired-end. In addition to ribosomal and non-characterized proteins, the most abundant transcripts encode putative transport/binding, lipocalin/lipocalin-like, and bactericidal/permeability-increasing-like proteins. Transcripts coding for putative canonical toxins described in venomous snakes were also identified. This transcriptional profile suggests a more complex function than previously recognized for this enigmatic organ.

Male infertility-related molecules involved in sperm-oocyte fusion

Male infertility has become a very serious problem in the human reproduction system, but the molecular mechanism of infertility remains largely unknown. Fertilization is the phenomenon in which a sperm and oocyte find each other, interact, and fuse. Sperm-oocyte fusion-related factors on the sperm side play crucial roles in male infertility. For example, IZUMO1 is well-known as a sperm protein essential for fusion of a sperm and oocyte, but its dysfunction or mutation can result in male infertility. Recent studies showed a novel sperm protein named Bactericidal/permeability-increasing protein (BPI), which takes part in the sperm-oocyte fusion process. The complexity and expected redundancy of the factors involved makes the process intricate, with a still poorly understood mechanism, which is difficult to comprehend in full detail. This review summarizes the known molecules involved in the process of sperm-oocyte fusion, mainly focusing on the relevant factors on the sperm side, whose dysregulation may potentially be associated with male infertility. New insights may come from these molecules in this review, can facilitate the development of new treatments of male infertility, and may have a diagnostic value in infertility.

Identification and expression analysis on bactericidal permeability-increasing protein/lipopolysaccharide-binding protein of blunt snout bream, Megalobrama amblycephala

Bactericidal permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) belong to the lipid transfer protein/lipopolysaccharide-binding protein family and play a critical role in the innate immune response to Gram-negative bacteria. In the present study, a novel BPI/LBP from blunt snout bream, Megalobrama amblycephala (maBPI/LBP) was isolated by RACE techniques. The open reading frame (ORF) of maBPI/LBP gene encoded a polypeptide of 474 amino acids with a putative 18-aa hydrophobic signal peptide. Structurally, the maBPI/LBP showed highly similar to those of BPI/LBPs from invertebrate and teleost, LBPs and BPIs from mammal, which contained an N-terminal BPI/LBP/CETP domain BPI1 with a LPS-binding domain, a C-terminal BPI/LBP/CETP domain BPI2, and proline-rich domain. The homologous identities of deduced amino acid sequences displayed that the maBPI/LBP possessed significant similarity (96.61% and 90.07%) with those of grass carp and common carp, respectively. The recombinant protein of maBPI/LBP showed effectively kill Gram-negative bacteria. The maBPI/LBP gene was expressed in a wide range of normal tested tissues, with the highest expression levels in the kidney. The experiments revealed that the mRNA expression of maBPI/LBP in spleen considerably up-regulated from 2 h to 8 h post LPS stimulation, and peaked rapidly at 2 h (7.40-fold, P < 0.05), which confirmed that maBPI/LBP was the absolute sensitive to LPS stimulation. Furthermore, the level of maBPI/LBP mRNA expression reached the maximum for a second time at 24 h after LPS stimulation. These results suggested that maBPI/LBP was a constitutive and inducible acute-phase protein contributing to the host immune defense against pathogenic bacterial infection in M. amblycephala. This study will further our understanding of the function of BPI/LBP and the molecular mechanism of innate immunity in teleost.