Defensins: defenders of human reproductive health

Stage-specific transcriptomic analysis reveals insights into the development, reproduction and biological function of allergens in the European house dust mite Dermatophagoides pteronyssinus

BACKGROUND

House dust mites (HDMs) such as Dermatophagoides pteronyssinus are major allergy elicitors worldwide, yet their gene expression across developmental stages remains underexplored. Herein, we report a comprehensive RNAseq analysis of larvae, nymphs, and adult males and females, mapped to a recently published high-quality genome with extended functional annotations.

RESULTS

Analysis of differentially expressed genes (DEG) revealed that female-biased expression was the most prevalent profile (16% of genes), while males exhibited the highest fold-change differences. DEG data, combined with network clustering and functional enrichment analysis, highlighted distinct genes and biological processes for each stage and sex: females showed upregulation of genes related to cell division and oogenesis, with vitellogenins among the most abundant transcripts; males exhibited increased expression of genes encoding putative seminal fluid proteins (e.g. endopeptidases, serpins, antimicrobial peptides), and those involved in reproductive regulation (e.g. testis-specific serine kinases); while juveniles displayed enhanced expression of genes related to energy metabolism and growth. Further analysis of endocrine pathways revealed non-canonic mechanisms compared to insect models, particularly in ecdysteroid and sesquiterpenoid biosynthesis and regulation. Expression patterns in genes involved in cuticle formation were also identified, reflecting their role in developmental transitions and sexual differentiation. Allergen and allergen-related gene expression showed an overall increase in feeding juveniles, as well as sex-biased expression, with Der p 27 upregulated in females. These findings provide insight into the physiological roles of allergens in digestion, immunity, and muscle formation, among other functions. Additionally, seven new horizontally transferred genes, including a DNA-repair photolyase linked to females, and novel multigene families (e.g. 119 male-specific beta-propeller proteins, 70 hypothetical cuticular proteins, 23 tetraspanin-like proteins, 5 female-associated putative odorant-binding proteins) were identified.

CONCLUSIONS

This study provides the first genome-wide transcriptomic analysis of a HDM across life stages and sexes, expanding our understanding of the molecular mechanisms underlying mite development, sexual reproduction, and allergen expression. The generated data, fully available via supplementary spreadsheet and the ORCAE online platform, provide a valuable foundation for future allergy research and the development of new mite control strategies.

Selective recognition of bacterial phospholipids by antimicrobial peptides: Employing a host-guest-mediated competitive inhibition strategy

The distinct phospholipid compositions of bacterial and mammalian cell membranes offer a promising target for the development of antimicrobial peptides (AMPs). However, distinguishing between the similarly charged anionic phospholipids-bacterial phosphatidylglycerol (PG) and mammalian phosphatidylserine (PS)-poses a significant challenge. Here we introduce a competitive inhibition strategy that leverages host-guest interactions to enable AMPs to selectively recognize PG without engaging with PS. After analyzing the binding interactions of various radially amphiphilic AMPs (RAPs), host molecules, and phospholipids, we discovered that a RAP, named C6HO, exhibited a higher affinity for cucurbit[7]uril (CB[7]) compared to PS, yet a lower affinity than for PG. Consequently, CB[7] functions as a competitive inhibitor: by forming a complex with C6HO upon simple mixing, it prevents C6HO from interacting with PS. Notably, PG can outcompete CB[7] for binding to C6HO within the complex, leading to the aggregation of PG molecules and the subsequent disruption of membranes rich in PG. Furthermore, the competitive inhibitor CB[7] effectively neutralizes C6HO's cytotoxic effects on mammalian cells while preserving the antimicrobial potency of C6HO. In vivo experiments in a subcutaneous infection model demonstrated that CB[7] reduced both systemic and local toxicity of C6HO without compromising its antimicrobial efficacy. Our study presents a strategy for the specific recognition of bacterial phospholipids and the design of highly selective AMPs.

Natural Human Antimicrobial Peptides and Female Reproductive Tract Infections

Female reproductive tract infections (RTIs) are a major health challenge worldwide and are the leading cause of infertility and adverse pregnancy outcomes. The rising incidence of RTIs highlights their status as a major public health issue. Microbial dysbiosis, particularly bacterial, fungal, and viral infections, constitutes the primary etiological factor disrupting female reproductive health. Antimicrobial peptides (AMPs) are evolutionarily conserved host defense molecules that exhibit broad-spectrum antimicrobial activity against pathogens, as well as anti-inflammatory and immunomodulatory properties. This review systematically summarizes the structural diversity, biological sources, and mechanistic pathways of human-derived AMPs in combating RTIs, with a particular emphasis on their therapeutic potential in fertility preservation. Emerging evidence suggests AMPs as promising alternatives to conventional antibiotics in the post-antibiotic era.

Genetic insights into the immunological basis of male infertility: a translational perspective

OBJECTIVE

To elaborate the causal relationships between specific immunocyte phenotypes and male infertility.

DESIGN

Mendelian randomization using genome-wide association study data.

SUBJECTS

Large cohorts of European ancestry.

EXPOSURE

731 immunocyte phenotypes or male infertility.

MAIN OUTCOMES MEASURES

Genetic variants were used as instrumental variables to infer causality, minimizing confounding and bias. The causal associations were assessed using the inverse variance-weighted (IVW) method for primary analysis, and the findings were validated using MR-Egger, Weighted Median, Simple Mode, and Weighted Mode approaches. Additional sensitivity analyses were performed to validate the robustness of the findings.

RESULTS

Our analysis identified significant causal associations between specific immunocyte phenotypes and male infertility. Phenotypes such as naive-mature B cell %lymphocyte (odds ratio [OR] = 1.257) and IgD- CD38dim %B cell (OR = 1.100) were positively associated with increased infertility risk, whereas phenotypes like CD39+ CD8br %T cell (OR = 0.856) and B cells activator of the TNF-α family receptor (BAFF-R) on transitional (OR = 0.833) were negatively associated, suggesting a protective effect. Additionally, reverse MR analysis revealed that male infertility might causally affect certain immunocyte phenotypes, including CD14- CD16+ monocyte %monocyte (OR = 1.049).

CONCLUSION

This study provides robust evidence for the causal role of specific immunocyte phenotypes in male infertility and highlights the bidirectional relationship between immune function and reproductive health. These findings provide new insights into the immunological factors contributing to male infertility and suggest potential biomarkers and therapeutic targets for future research and clinical interventions.

Structure, function, and therapeutic potential of defensins from marine animals

Defensins are a type of host defense peptides (HDPs), belonging to a family of cationic antimicrobial peptides (AMPs) that exhibit activity against various infectious microorganisms including bacteria, viruses, and fungi. Due to the uniqueness of the ocean's ecological environment, defensins from marine animals have a rich biodiversity and some special molecular features so as to possess significant potential. They exert antibacterial activity by binding to cell membranes, forming specific channels, or interacting with lipid II. These peptides can be utilized through various nanotechnologies, such as antimicrobial peptide-antibiotic conjugates, nanonets, and nanoparticle-based drug delivery systems, to enhance their antibacterial activities and broaden their spectra. This review summarizes the structural characteristics and classification of defensins from marine animals (mainly fish and shellfish), outlines their evolutionary trajectory, and discusses their antibacterial, antiviral, immune-regulation, and reproductive functions. Finally, the future therapeutic potential of defensins from marine animals is highlighted for fighting antibiotic resistance and treating other diseases. This review provides new insights into the future development of marine resources and natural peptides.

The dual role of IL-17 in periodontitis regulating immunity and bone homeostasis

Periodontitis is a common dysbiotic bacteria-induced inflammatory disease characterized by alveolar bone resorption, leading to tooth loss. Interleukin-17 (IL-17) is a critical cytokine with dual roles in periodontium, which exerts the function of host defense, including neutrophil recruitment, phagocytosis, and mucosal immunity. However, excessive expression of IL-17 causes persistent chronic inflammation, local tissue breakdown, and bone loss. This review highlights the protective and pathological functions of IL-17 on immunity and bone homeostasis in inflammatory bone-related diseases. We also provide the latest findings with IL-17 knockout mice in periodontitis and highlight complex immune responses under various experimental models. This may provide a critical perception of inflammatory bone-related disease management using an immune-modulating strategy.

Advances in the Prevention of Cervical Cancer by Anti-Human Papillomavirus Agents

BACKGROUND

Cervical cancer remains a major global health threat for women, primarily driven by human papillomavirus (HPV) infection. While HPV vaccination serves as the cornerstone of prevention, disparities in vaccine accessibility persist across low-income countries. Secondary prevention through screening faces challenges in public engagement, often leading to late-stage diagnoses. Recent advancements in novel anti-HPV drugs offer expanded opportunities for cervical cancer management.

AIM

This review examines emerging anti-HPV therapeutics to provide insights into innovative strategies for cervical cancer prevention and treatment.

METHODS

We conducted a systematic analysis of published studies investigating anti-HPV agents, focusing on their molecular mechanisms and clinical efficacy in cervical cancer prevention.

RESULTS & CONCLUSIONS

Multiple promising anti-HPV agents have been identified, including 3-hydroxyphthalic anhydride-modified bovine β-lactoglobulin (3HP-β-LG), carrageenan, defensins, and 25-hydroxycholesterol (25HC). These compounds exert antiviral effects through distinct mechanisms: 3HP-β-LG competitively inhibits viral attachment, carrageenan blocks HPV entry via heparan sulfate mimicry, defensins inhibit the dissociation of viral capsid, and 25HC activates cholesterol-mediated antiviral pathways. They have demonstrated strong inhibitory effects on HPV infection, making them novel therapeutic candidates for the prevention and treatment of cervical cancer.

Advances in Antimicrobial Peptides: Mechanisms, Design Innovations, and Biomedical Potential

This comprehensive review explores the advancements in the study of antimicrobial peptides (AMPs), highlighting their potential as promising alternatives to conventional antibiotics in the context of growing antibiotic resistance. AMPs are small molecular proteins found ubiquitously in nature, exhibiting broad-spectrum antimicrobial activity, including antibacterial, antiviral, and antifungal effects, and are vital components of the innate immune system. Due to their non-specific membrane-disrupting mechanism, AMPs are emerging as effective candidates for novel anti-infective agents. The integration of AMPs with biomaterials, such as nanoparticles, liposomes, polymers, and hydrogels, enhances their stability and efficacy while offering multifunctional therapeutic benefits. These combinations promote diverse antibacterial mechanisms, including membrane disruption, intracellular metabolic interference, cell wall modulation, and immune system activation. Despite challenges, such as toxicity, stability, and resistance, innovative strategies including computer-aided design and structural modification show promise in optimizing AMPs' activity, targeting precision, and biocompatibility. The potential for AMPs in clinical applications remains highly promising, with significant opportunities for overcoming antimicrobial resistance through novel AMP-based therapeutic strategies.

Lithocholic Acid Oleate Preparative Synthesis and Its Formulation with Lithocholic Acid as a Preventive Antiviral: In Vitro and In Vivo Assays Against HSV-1 as a Viral Infection Model

The discovery and design of antiviral agents have gained unprecedented significance due to the emergence of global health threats. The use of synthetic chemistry has enabled the modification of existing molecules and the creation of entirely novel compounds. In our laboratory, we have enzymatically synthesized a novel bioconjugate, lithocholic acid oleate (LO), derived from lithocholic acid (LCA), a bile acid that has been proven by researchers to exhibit antiviral activity in vitro. The study presented herein describes the preparative synthesis, formulation, and evaluation of LO both in vitro and in vivo for its antiviral activity against human herpes simplex virus 1 (HSV-1) as a model of viral infection. Evaluation of cytotoxicity using A549 cells indicated that a combination of LO (400 μM) and LCA (30 μM) exhibited a favorable safety profile while effectively inhibiting HSV-1 infection comparable to acyclovir treatment. Furthermore, in the in vivo assay, animals treated with an oily formulation containing 7% LO; 0.50% LCA; and 3% oleic acid (OA), 48 h prior to virus exposure, showed results even superior to a 5% acyclovir commercial formulation in terms of scar formation and wound recovery. These promising results enable the development of new preventive products against HSV-1 and probably other viruses.

Comparative analysis of proteomics and transcriptomics reveals novel mechanism underlying the antibacterial activity and immune-enhancing properties of horse milk

Background

Horse milk is a highly valuable organic food that is a promising alternative to cow milk, exhibiting plenty of healthy and immune benefits to human. However, identification of proteins associated human wellness and underlying molecular mechanism in horse milk remain unclear.

Methodology

Label-free mass spectrometry-based protein quantification technology was employed to investigate protein composition of animal milk, including cow, goat, camel and horse milk. Prokaryotic expression and disk diffusion assay were applied to acquire and evaluate in vitro antimicrobial activity of candidate proteins. RAW264.7 macrophage model cell line was used to validate effect of proteins on cytotoxicity, apoptosis and immune induction. ROS probe detected cell ROS change and RT-qPCR verified expression of immune response genes induced by proteins. Microscopy was used to observe the effects of protein on the morphological characteristics of bacteria, further transcriptome analysis was performed to investigate transcriptional changes of bacteria induced by candidate proteins.

Results

A total of 1,335 proteins was identified in cow, goat, camel and horse milk. GO enrichment analysis showed that the proteins related to protein degradation were highly expressed in horse milk compared to other three types of milk, contributing to easier assimilation and palatability. KEGG analysis showed that horse milk contained abundant antimicrobial associated proteins relevant to pathogenic bacterial resistance, leading to the decreased risk of pathogenic diseases. A higher accumulation of proteins associated with caffeine metabolism, amino acid biosynthesis, and glycolysis/gluconeogenesis in horse milk contributes to its distinctive flavor. Notably, highly expressed proteins in horse milk were closely linked to immune signaling pathways, functioning as immune modulators. Importantly, we identified four highly expressed antimicrobial associated proteins in horse milk including LPO, B2M, CD14 and PGL, among them, PGL functioned dually by in vitro antibacterial activity and immune activation. Further transcriptome analysis demonstrated that PGL exerted significant transcriptional changes to bacteria. Enrichment analysis showed PGL could inhibit growth of P. aeruginosa and E. coli by repressing the biosynthesis of secondary metabolites.

Conclusion

Comparative proteomics revealed immune enhancement and nutrient composition of horse milk compared to cow, goat and camel milk. Identification of PGL showed antibacterial activity and potential medicinal value.

The Role of Beta-Defensin 2 in Preventing Preterm Birth with Chorioamnionitis: Insights into Inflammatory Responses and Epithelial Barrier Protection

Antimicrobial peptides, such as beta-defensin 2 (BD2), are vital in controlling infections and immune responses. In this study, we investigated the expression and role of BD2 in the amniotic membrane and human amniotic epithelial cells (hAECs) from patients with preterm birth and chorioamnionitis, focusing on its regulation of inflammatory cytokines and its protective effect on the epithelial barrier. Our results show increased BD2 expression in chorioamnionitis, and Lipopolysaccharide (LPS)-induced inflammation increased BD2 release from hAECs in a dose- and time-dependent manner. BD2 treatment effectively modulated the inflammatory response by reducing pro-inflammatory cytokines (IL-6, IL-1β) and enhancing the release of the anti-inflammatory cytokine IL-10. Additionally, BD2 helps preserve epithelial barrier integrity by restoring E-cadherin expression and reducing Snail expression in inflamed hAECs. In an LPS-induced preterm birth mouse model, BD2 treatment delayed preterm delivery and reduced inflammatory cytokine levels. These results suggest that BD2 plays a protective role in preventing preterm birth by regulating inflammation and maintaining epithelial barrier function, highlighting its therapeutic potential for inflammation-related preterm birth.

Prevalence of neutropenia in the U.S. among reproductive-aged women: a population-based analysis of NHANES 2013-2020

BACKGROUND

Infertility is one of the prominent public health concerns nationwide. Neutrophils, despite their established significance as vital players in both inflammatory and immune processes, have been studied scarcely in terms of their effect on female infertility. The present study aimed to determine the prevalence of neutropenia among women of reproductive age in the U.S. to contribute valuable insights to the broader context of reproductive health.

METHODS

The present study was designed as a cross-sectional investigation. The data of 5,250 female participants aged 18-45 years were obtained from the National Health and Nutrition Examination Survey (NHANES) conducted between the years 2013 and 2020. The representativeness of the population was ensured by conducting statistical assessments based on NHANES weights. A logistic regression model was established to assess the hematologic parameters across the distinct populations stratified according to age, ethnicity, smoking status, and infertility. Multivariate logistic regression was performed next, and weighted odds ratios along with the 95% confidence interval values were calculated, which assisted in predicting the prevalence of neutropenia among the female participants.

RESULTS

The data of a total of 5,250 female participants, representing a multiracial population of 51.17 million in the United States, were analyzed in the present study. Meanwhile, the estimated neutropenia incidence was 7.09% (95% CI: 6.16-8.01%), which indicated a prevalence among approximately 36.2 million U.S. citizens. In comparison to white subjects, black subjects exhibited a significantly lower average leukocyte count, with a mean difference (MD) of 1.16 × 109/L (P < 0.001), along with a lower neutrophil count (MD: 1.09 × 109/L; P < 0.001). It is noteworthy that a substantial decrease was noted in the distribution graphs of both neutrophil and leukocyte counts among the black subjects. Moreover, compared to non-smokers in the racial populations, including white, Mexican American, and black people, the smokers exhibited significantly elevated mean leukocyte count and mean neutrophil count. The logistic regression analysis indicated an elevated risk of neutropenia among black individuals and females with infertility.

CONCLUSIONS

Neutropenia appears to have a higher prevalence in the general population compared to that acknowledged previously. The findings of the present study indicated association between neutropenia and infertility. This highlighted the importance of directing increased attention toward neutropenia in the context of both research and clinical practice.

Single-cell RNA sequencing unveils dynamic transcriptional profiles during the process of donkey spermatogenesis and maturation

INTRODUCTION

With the increasing demand for donkey production, there has been a growing focus on the breeding of donkeys. However, our current understanding of the mechanisms underlying spermatogenesis and maturation in donkeys during reproduction remains limited.

OBJECTIVES

This study is to provide a comprehensive single-cell landscape analysis of spermatogenesis and maturation in donkeys.

METHODS

In this study, we employed single-cell RNA sequencing to investigate cell composition, gene expression patterns, and regulatory roles during spermatogenesis and maturation in donkeys.

RESULTS

The expression patterns of CDK1, CETN3, and UBE2J1 were found to be indicative of specific germ cells during donkey spermatogenesis. Additionally, the DEFB121, ELSPBP1, and NPC2 genes were specifically identified in the principal cells of the donkey epididymis.

CONCLUSIONS

We performed single-cell RNA sequencing to analyze the cellular composition and spatial distribution of donkey testis and epididymis, thereby generating comprehensive transcriptional atlases at the single-cell resolution.

Molecular profiling unveils pyroptosis markers in preterm birth

Through a comprehensive examination of pyroptosis-related differential expressed genes (PRDEGs), this work investigates the molecular complexities of spontaneous preterm birth (SPTB), also known as premature delivery, before the due date. Through the process of merging and correcting batch effects in the GSE120480 and GSE73714 datasets, we were able to identify 36 PRDEGs that exhibited significant expression differentiation in SPTB. Through functional enrichment and pathway analysis, their importance in amino acid transport and cytokine receptor interaction has been highlighted. Among the genes that have emerged as crucial, CEBPA, APOA1, and CEP55 have been identified. The relevance of these molecules was demonstrated using experimental knockdowns, which also suggested that they could be used as molecular biomarkers and therapeutic targets for SPTB.

β-Defensin versus conventional markers of inflammation in periprosthetic joint infection: a retrospective study

Background

Diagnosing periprosthetic joint infection (PJI) remains a significant challenge for healthcare professionals. Commonly utilized inflammatory markers include erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and white blood cells (WBC). Human β-defensin 1 (β-defensin) is an antimicrobial peptide elevated in infection, yet its diagnostic value for PJI has not been explored. The purpose of this study was to evaluate the efficacy of synovial β-defensin as a diagnostic marker for PJI and to compare its performance with ESR, serum CRP, and WBC.

Methods

We conducted a single-center retrospective study from October 2022 to June 2023. A total of 105 joint fluid samples from revision patients at the Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra were collected intraoperatively (71 hips, 34 knees) and frozen. According to MSIS criteria, 64 patients were defined as positive for PJI and the remaining 41 were negative. Synovial β-defensin levels were quantified using ELISA, serum CRP levels by immunoturbidimetry, and blood ESR and WBC were analyzed. Sensitivity and specificity were determined using ROC curves, and diagnostic performance was compared using the area under the curve (AUC). Cut-off values for diagnosing PJI were established.

Results

Levels of synovial β-defensin, ESR, serum CRP, and WBC were significantly higher in the PJI group compared to the non-PJI (P < 0.0001). The AUCs were 0.948 for β-defensin, 0.884 for ESR, 0.902 for CRP, and 0.767 for WBC, with a combined AUC of 0.994. Sensitivity/specificity for β-defensin, ESR, CRP, and WBC were 0.966/0.830, 0.887/0.791, 0.930/0.771, and 0.820/0.682, respectively. Optimal predictive cut-off values were 1105.8 pg/mL for β-defensin, 11.5 mm/h for ESR, 5.55 mg/L for CRP, and 7.3 × 103/mm3 for WBC.

Conclusion

The synovial β-defensin assay demonstrated greater sensitivity and specificity for the diagnosis of PJI compared to ESR, serum CRP and WBC. Therefore, β-defensin shows promise as a diagnostic marker for PJI. Simultaneous determination of all markers may increase diagnostic confidence.

The antibacterial defence role of β-defensin in the seahorse testis

Seahorses represent the only known group of animals with male pregnancy. Seahorses have small testis that produce a limited quantity of sperm. To date, the response of this immune-privileged organ to pathogenic infections has not been reported. β-defensin (BD) is an important innate immune defence factor against pathogens in vertebrate testis. To elucidate its immunoprotection in seahorse testis, we identified the Hippocampus erectus β-defensin (HeBD) sequence in its genome via phylogenetic tree and protein-sequence structure analysis. Gene-expression analysis showed that HeBD was highly expressed in the seahorse testis and was significantly upregulated after bacterial infection, indicating that HeBD expression was related to testicular immune responses. Furthermore, antibacterial activity testing demonstrated that the mature HeBD peptide exhibited broad-spectrum aggregation activity but only moderate antibacterial activity. We found that the mature HeBD mature significantly neutralised bacterial endotoxin activity. In conclusion, our results imply that HeBD serves an immunoprotective role in seahorse testis.

Correlation and Clinical Significance of HBD-2 and CXCL-1/2 Levels at Skin Lesions with Psoriasis Vulgaris Severity

OBJECTIVE

This study was performed to explore the clinical significance of the expression of human beta-defensin 2 (HBD-2) and chemokine ligand 1/2 (CXCL-1/2) in psoriasis vulgaris.

METHODS

This study retrospectively included the study group (n = 160) and control group (n = 100) for analysis. The levels of inflammatory indicators, blood biochemical indicators, and immune indicators using ELISA. The psoriasis area and severity index (PASI) was used to evaluate disease severity. Levels of HBD-2, CXCL-1, CXCL-2 and CCL20 were determined by RT-PCR. The correlations of HBD-2, CXCL-1 and CXCL-2 levels with CCL20 and PASI scores were analyzed. The diagnostic value of HBD-2, CXCL-1 and CXCL-2 in psoriasis vulgaris was analyzed by ROC curve.

RESULTS

HBD-2, CXCL-1 and CXCL-2 were highly expressed in the lesions of psoriasis vulgaris patients, and were positively correlated with CCL20 and PASI score. HBD-2, CXCL-1 and CXCL-2 alone or in combination had high diagnostic value for psoriasis vulgaris and severe psoriasis, and the combined diagnostic value of the three was higher than that of a single indicator.

CONCLUSION

HBD-2, CXCL-1, and CXCL-2 levels are closely related to the severity of psoriasis vulgaris and can effectively diagnose the occurrence and progression of psoriasis vulgaris.

Immunoregulation and male reproductive function: Impacts and mechanistic insights into inflammation

This paper investigates the complex relationship between the immune system and male reproductive processes, emphasizing how chronic inflammation can adversely affect male reproductive health. The immune system plays a dual role; it protects and regulates reproductive organs and spermatogenesis while maintaining reproductive health through immune privilege in the testes and the activities of various immune cells and cytokines. However, when chronic inflammation persists or intensifies, it can disrupt this balance, leading to immune attacks on reproductive tissues and resulting in infertility.This study provides a detailed analysis of how chronic inflammation can impair sperm production, sperm quality, and the secretion of gonadal hormones both directly and indirectly. It also delves into the critical roles of testicular immune privilege, various immune cells, and cytokines in sustaining reproductive health and examines the impacts of infections, autoimmune diseases, and environmental factors on male fertility.

Biological function of sialic acid and sialylation in human health and disease

Sialic acids are predominantly found at the terminal ends of glycoproteins and glycolipids and play key roles in cellular communication and function. The process of sialylation, a form of post-translational modification, involves the covalent attachment of sialic acid to the terminal residues of oligosaccharides and glycoproteins. This modification not only provides a layer of electrostatic repulsion to cells but also serves as a receptor for various biological signaling pathways. Sialylation is involved in several pathophysiological processes. Given its multifaceted involvement in cellular functions, sialylation presents a promising avenue for therapeutic intervention. Current studies are exploring agents that target sialic acid residues on sialoglycans or the sialylation process. These efforts are particularly focused on the fields of cancer therapy, stroke treatment, antiviral strategies, and therapies for central nervous system disorders. In this review, we aimed to summarize the biological functions of sialic acid and the process of sialylation, explore their roles in various pathophysiological contexts, and discuss their potential applications in the development of novel therapeutics.

L-carnitine combined with traditional Chinese medicine for male infertility: A systematic review and meta-analysis

Background

Fertility rates are declining globally, and male infertility is increasingly recognized as a significant challenge. This study aims to present the latest findings on the effectiveness and safety of combining traditional Chinese medicine (TCM) with L-carnitine (LC) for treating male infertility.

Methods

We searched 8 databases. Randomized controlled trials of TCM combined with LC therapy versus LC alone in the treatment of male infertility. The outcome included: pregnancy rate, sperm motility, concentration, volume, viability and liquefaction time. Subgroup analyses were also performed according to type of TCM, type of dosage form, and different TCM treatments, and the source of the high heterogeneity was explored. The study is registered on PROSPERO (CRD42023421497).

Results

1129 subjects from 12 of the 1833 eligible studies fulfilled the criteria. Compared with LC treatment alone, the combination of TCM and LC significantly improved pregnancy rate [RR = 1.65, 95 % CI (1.37-2.00)], grade (a+b) sperm motility [SMD = 1.56, 95 % CI (1.12, 2.01)], grade (a) sperm motility [SMD = 1.04, 95 % CI (0.69, 1.38)], sperm concentration [SMD = 1.39, 95 % CI (0.91, 1.86)], and sperm viability [SMD = 1.72, 95 % CI (0.83, 2.60)]. Subgroup analyses indicated that Compound Xuanju Capsule and Yougui Capsule demonstrated better efficacy. And the decoction and not-decoction each had their own advantages.

Conclusions

The combination of TCM with LC can have a dual effect: increasing pregnancy rates and sperm quality. Therefore, this combination is a recommended therapeutic strategy and a more appropriate type of TCM can be selected according to the patient's own characteristics.

Characterisation of defensins across the marsupial family tree

Defensins are antimicrobial peptides involved in innate immunity, and gene number differs amongst eutherian mammals. Few studies have investigated defensins in marsupials, despite their potential involvement in immunological protection of altricial young. Here we use recently sequenced marsupial genomes and transcriptomes to annotate defensins in nine species across the marsupial family tree. We characterised 35 alpha and 286 beta defensins; gene number differed between species, although Dasyuromorphs had the largest repertoire. Defensins were encoded in three gene clusters within the genome, syntenic to eutherians, and were expressed in the pouch and mammary gland. Marsupial beta defensins were closely related to eutherians, however marsupial alpha defensins were more divergent. We identified marsupial orthologs of human DEFB3 and 6, and several marsupial-specific beta defensin lineages which may have novel functions. Marsupial predicted mature peptides were highly variable in length and sequence composition. We propose candidate peptides for future testing to elucidate the function of marsupial defensins.

Human β-defensins: The multi-functional natural peptide

The increasing threat of antibiotic resistance among pathogenic microorganisms and the urgent demand for new antibiotics require immediate attention. Antimicrobial peptides exhibit effectiveness against microorganisms, fungi, viruses, and protozoa. The discovery of human β-defensins represents a major milestone in biomedical research, opening new avenues for scientific investigation into the innate immune system and its resistance mechanisms against pathogenic microorganisms. Multiple defensins present a promising alternative in the context of antibiotic abuse. However, obstacles to the practical application of defensins as anti-infective therapies persist due to the unique properties of human β-defensins themselves and serious pharmacological and technical challenges. To overcome these challenges, diverse delivery vehicles have been developed and progressively improved for the conjugation or encapsulation of human β-defensins. This review briefly introduces the biology of human β-defensins, focusing on their multistage structure and diverse functions. It also discusses several heterologous systems for producing human β-defensins, various delivery systems created for these peptides, and patent applications related to their utilization, concluding with a summary of current challenges and potential solutions.

Systemic Factors Affecting Human Beta-Defensins in Oral Cavity

Human beta-defensins are host defense peptides with broad antimicrobial and inflammatory functions. In the oral cavity, these peptides are produced mainly by the keratinocytes of the epithelium; however, fibroblasts, monocytes, and macrophages also contribute to oral human beta-defensin expressions. The resident and immune cells of the oral cavity come into contact with various microbe-associated molecular patterns continuously and simultaneously. The overall antimicrobial cellular response is highly influenced by local and environmental factors. Recent studies have produced evidence showing that not only systemic chronic diseases but also systemic factors like hyperglycemia, pregnancy, the long-term use of certain vitamins, and aging can modulate oral cellular antimicrobial responses against microbial challenges. Therefore, the aim of this narrative review is to discuss the role of systemic factors on oral human beta-defensin expressions.

Effects of Ellagic Acid on Vaginal Innate Immune Mediators and HPV16 Infection In Vitro

Ellagic acid (EA) is a phenolic phytochemical found in many plants and their fruits. Vaginal epithelial cells are the first line of defense against pathogen invasion in the female reproductive tract and express antimicrobial peptides, including hBD2 and SLPI. This study investigated the in vitro effects of EA (1) on vaginal innate immunity using human vaginal epithelial cells, and (2) on HPV16 pseudovirus infection. Vaginal cells were cultured in the presence or absence of EA, and the expression of hBD2 and SLPI was determined at both transcriptional and translational levels. In addition, secretion of various cytokines and chemokines was measured. Cytotoxicity of EA was determined by CellTiter-blue and MTT assays. To investigate the ability of EA to inhibit HPV16 infection, EA was used to treat HEK-293FT cells in pre-attachment and adsorption steps. We found significant increases in both hBD2 mRNA (mean 2.9-fold at 12.5 µM EA, p < 0.001) and protein (mean 7.1-fold at 12.5 µM EA, p = 0.002) in response to EA. SLPI mRNA also increased significantly (mean 1.4-fold at 25 µM EA, p = 0.01), but SLPI protein did not. Secretion of IL-2 but not of other cytokines/chemokines was induced by EA in a dose-dependent manner. EA was not cytotoxic. At the pre-attachment step, EA at CC20 and CC50 showed a slight trend towards inhibiting HPV16 pseudovirus, but this was not significant. In summary, vaginal epithelial cells can respond to EA by producing innate immune factors, and at tested concentrations, EA is not cytotoxic. Thus, plant-derived EA could be useful as an immunomodulatory agent to improve vaginal health.

Mycobacterium tuberculosis suppresses host antimicrobial peptides by dehydrogenating L-alanine

Antimicrobial peptides (AMPs), ancient scavengers of bacteria, are very poorly induced in macrophages infected by Mycobacterium tuberculosis (M. tuberculosis), but the underlying mechanism remains unknown. Here, we report that L-alanine interacts with PRSS1 and unfreezes the inhibitory effect of PRSS1 on the activation of NF-κB pathway to induce the expression of AMPs, but mycobacterial alanine dehydrogenase (Ald) Rv2780 hydrolyzes L-alanine and reduces the level of L-alanine in macrophages, thereby suppressing the expression of AMPs to facilitate survival of mycobacteria. Mechanistically, PRSS1 associates with TAK1 and disruptes the formation of TAK1/TAB1 complex to inhibit TAK1-mediated activation of NF-κB pathway, but interaction of L-alanine with PRSS1, disables PRSS1-mediated impairment on TAK1/TAB1 complex formation, thereby triggering the activation of NF-κB pathway to induce expression of AMPs. Moreover, deletion of antimicrobial peptide gene β-defensin 4 (Defb4) impairs the virulence by Rv2780 during infection in mice. Both L-alanine and the Rv2780 inhibitor, GWP-042, exhibits excellent inhibitory activity against M. tuberculosis infection in vivo. Our findings identify a previously unrecognized mechanism that M. tuberculosis uses its own alanine dehydrogenase to suppress host immunity, and provide insights relevant to the development of effective immunomodulators that target M. tuberculosis.

Peptide Dendrimer-Based Antibacterial Agents: Synthesis and Applications

Pathogenic bacteria cause the deaths of millions of people every year. With the development of antibiotics, hundreds and thousands of people's lives have been saved. Nevertheless, bacteria can develop resistance to antibiotics, rendering them insensitive to antibiotics over time. Peptides containing specific amino acids can be used as antibacterial agents; however, they can be easily degraded by proteases in vivo. To address these issues, branched peptide dendrimers are now being considered as good antibacterial agents due to their high efficacy, resistance to protease degradation, and low cytotoxicity. The ease with which peptide dendrimers can be synthesized and modified makes them accessible for use in various biological and nonbiological fields. That is, peptide dendrimers hold a promising future as antibacterial agents with prolonged efficacy without bacterial resistance development. Their in vivo stability and multivalence allow them to effectively target multi-drug-resistant strains and prevent biofilm formation. Thus, it is interesting to have an overview of the development and applications of peptide dendrimers in antibacterial research, including the possibility of employing machine learning approaches for the design of AMPs and dendrimers. This review summarizes the synthesis and applications of peptide dendrimers as antibacterial agents. The challenges and perspectives of using peptide dendrimers as the antibacterial agents are also discussed.

Intestinal Mucosal Immune Barrier: A Powerful Firewall Against Severe Acute Pancreatitis-Associated Acute Lung Injury via the Gut-Lung Axis

The pathogenesis of severe acute pancreatitis-associated acute lung injury (SAP-ALI), which is the leading cause of mortality among hospitalized patients in the intensive care unit, remains incompletely elucidated. The intestinal mucosal immune barrier is a crucial component of the intestinal epithelial barrier, and its aberrant activation contributes to the induction of sustained pro-inflammatory immune responses, paradoxical intercellular communication, and bacterial translocation. In this review, we firstly provide a comprehensive overview of the composition of the intestinal mucosal immune barrier and its pivotal roles in the pathogenesis of SAP-ALI. Secondly, the mechanisms of its crosstalk with gut microbiota, which is called gut-lung axis, and its effect on SAP-ALI were summarized. Finally, a number of drugs that could enhance the intestinal mucosal immune barrier and exhibit potential anti-SAP-ALI activities were presented, including probiotics, glutamine, enteral nutrition, and traditional Chinese medicine (TCM). The aim is to offer a theoretical framework based on the perspective of the intestinal mucosal immune barrier to protect against SAP-ALI.

The antimicrobial peptide Abaecin alleviates colitis in mice by regulating inflammatory signaling pathways and intestinal microbial composition

Abaecin is a natural antimicrobial peptide (AMP) rich in proline from bees. It is an important part of the innate humoral immunity of bees and has broad-spectrum antibacterial ability. This study aimed to determine the effect of Abaecin on dextran sulfate sodium (DSS) -induced ulcerative colitis (UC) in mice and to explore its related mechanisms. Twenty-four mice with similar body weight were randomly divided into 4 groups. 2.5% DSS was added to drinking water to induce colitis in mice. Abaecin and PBS were administered rectally on the third, fifth, and seventh days of the experimental period. The results showed that Abaecin significantly alleviated histological damage and intestinal mucosal barrier damage caused by colitis in mice, reduced the concentration of pro-inflammatory cytokines IL-1β, IL-6, TNF-α, IFN-γ, and the phosphorylation of NF-κB / MAPK inflammatory signaling pathway proteins, and improved the composition of intestinal microorganisms. These findings suggest that Abaecin may have potential prospects for the treatment of UC.

Microfluidic chip as a promising evaluation method in assisted reproduction: A systematic review

The aim of assisted reproductive technology (ART) is to select the high-quality sperm, oocytes, and embryos, and finally achieve a successful pregnancy. However, functional evaluation is hindered by intra- and inter-operator variability. Microfluidic chips emerge as the one of the most powerful tools to analyze biological samples for reduced size, precise control, and flexible extension. Herein, a systematic search was conducted in PubMed, Scopus, Web of Science, ScienceDirect, and IEEE Xplore databases until March 2023. We displayed and prospected all detection strategies based on microfluidics in the ART field. After full-text screening, 71 studies were identified as eligible for inclusion. The percentages of human and mouse studies equaled with 31.5%. The prominent country in terms of publication number was the USA (n = 13). Polydimethylsiloxane (n = 49) and soft lithography (n = 28) were the most commonly used material and fabrication method, respectively. All articles were classified into three types: sperm (n = 38), oocytes (n = 20), and embryos (n = 13). The assessment contents included motility, counting, mechanics, permeability, impedance, secretion, oxygen consumption, and metabolism. Collectively, the microfluidic chip technology facilitates more efficient, accurate, and objective evaluation in ART. It can even be combined with artificial intelligence to assist the daily activities of embryologists. More well-designed clinical studies and affordable integrated microfluidic chips are needed to validate the safety, efficacy, and reproducibility. Trial registration: The protocol was registered in the Open Science Frame REGISTRIES (identification: osf.io/6rv4a).

Ovarian sex steroid and epithelial control of immune responses in the uterus and oviduct: human and animal models†

The female reproductive tract (FRT), including the uterus and oviduct (Fallopian tube), is responsible for maintaining an optimal microenvironment for reproductive processes, such as gamete activation and transportation, sperm capacitation, fertilization, and early embryonic and fetal development. The mucosal surface of the FRT may be exposed to pathogens and sexually transmitted microorganisms due to the opening of the cervix during mating. Pathogens and endotoxins may also reach the oviduct through the peritoneal fluid. To maintain an optimum reproductive environment while recognizing and killing pathogenic bacterial and viral agents, the oviduct and uterus should be equipped with an efficient and rigorously controlled immune system. Ovarian sex steroids can affect epithelial cells and underlying stromal cells, which have been shown to mediate innate and adaptive immune responses. This, in turn, protects against potential infections while maintaining an optimal milieu for reproductive events, highlighting the homeostatic involvement of ovarian sex steroids and reproductive epithelial cells. This article will discuss how ovarian sex steroids affect the immune reactions elicited by the epithelial cells of the non-pregnant uterus and oviduct in the bovine, murine, and human species. Finally, we propose that there are regional and species-specific differences in the immune responses in FRT.

β-defensin 2 protects against Escherichia coli-induced acute urinary tract infection by downregulating β-catenin

β-defensin 2 (BD2) is a small cationic peptide that exerts a critical role in host defense against bacterial infections. Here, we aimed to investigate the role of BD2 in protecting against acute urinary tract infection (AUTI) caused by Escherichia coli (UPEC). Here, LPS-induced human urinary bladder epithelial cell (HCV-29) model and UPEC-induced mice model were used for assessing AUTI. Visceral organ lesions of mice following treatment was assessed by HE staining. Cell viability was determined by CCK-8 assay. Permeability in HCV-29 cells was analyzed in Transwell assay. Expression of inflammatory factors (IL-1β, IL-6, and TNF-α) was measured by ELISA assay. The levels of BD2, β-catenin and tight-junction proteins (ZO-1, Occludin, and Claudin-1) were detected by RT-qPCR, western blotting, immunofluorescence or immunohistochemistry. Our results showed that BD2 was lowly expressed and β-catenin showed the reverse trend in response to bacterial infection in vitro and in vivo. BD2 overexpression alleviated the decreased cell viability, increased cell permeability, upregulation of inflammatory factors, downregulation of tight-junction protein and high β-catenin expression in LPS-induced HCV-29 cells, which may contribute to the negative regulation of β-catenin expression. Furthermore, BD2 overexpression attenuated the bacterial infection of tissues, high levels of inflammatory factors and β-catenin, and low levels of tight-junction proteins in mice stimulated with UPEC. This study showed that BD2 played a crucial role in protecting against AUTI caused by gram-negative bacteria through suppressing β-catenin expression. Targeting BD2 may provide a potential therapeutic approach for the prevention and treatment of AUTI.

DEFB126 2-nt Deletion (rs11467417) as a Potential Risk Factor for Chlamydia Trachomatis Infection and Subsequent Infertility in Iranian Men

Background

Chlamydia trachomatis (CT) is one of the most prevalent sexually transmitted infections, causing genital tract infections and infertility. Defensins have an immunomodulatory function and play an important role in sperm maturation, motility, and fertilization. DEFB126 is present on ejaculated spermatozoa and is essential for them to pass through the female reproductive tract. The purpose of the study was to determine the frequency of the 2-nt deletion of the DEFB126 (rs11467417) in Iranian infertile males with a recurrent history of CT.

Methods

Semen samples of 1080 subfertile males were investigated. Among patients who had CT-positive results, sperm DNA from 50 symptomatic and 50 asymptomatic patients were collected for the DEFB126 genotype analysis. Additionally, a control group comprising 100 DNA samples from individuals with normal spermogram and testing negative for CT was included in the study. The PCR-sequencing for detecting the 2-nt deletion of the second exon of the DEFB126 was performed.

Results

The Chi-squared test comparing all three groups revealed no significant difference across the different genotypes. Moreover, no significant difference between the symptomatic and asymptomatic groups was seen. However, analysis within CT-positive patients and controls demonstrated significant difference between the frequencies of homozygous del/del.

Conclusion

The higher frequency of the 2-nt deletion of the DEFB126 in CT- positive patients suggests that the occurrence of mutations in the DEFB-126 may cause the impairment of the antimicrobial activity of the DEFB126 protein and consequently makes individuals more susceptible to infections such as CT.

Antimicrobial Peptides Targeting Streptococcus mutans: Current Research on Design, Screening and Efficacy

Antimicrobial peptides (AMPs) are small-molecule peptides that play a vital role in the nonspecific immune defense system of organisms. They mainly kill microorganisms by physically destroying the cell membrane and causing the leakage of contents. AMPs have attracted much attention as potential alternatives to antibiotics due to their low susceptibility to resistance. Streptococcus mutans (S. mutans) is one of the main causative agents of human dental caries. The design, screening, and efficacy evaluation of AMPs targeting S. mutans offer new possibilities for the prevention and treatment of oral diseases, especially dental caries, in the future. This article reviews AMPs from different sources that have inhibitory effects on S. mutans, discusses the mechanism of action of AMPs against S. mutans biofilms, and focuses on the research progress of screening methods, design modification, and biological activity evaluation of AMPs. We hope to provide insights and reference value for the development of new biologics.

Global, regional and national burden of male infertility in 204 countries and territories between 1990 and 2019: an analysis of global burden of disease study

BACKGROUND

Many countries and regions have experienced male fertility problems due to various influencing factors, especially in less developed countries. Unlike female infertility, male infertility receives insufficient attention. Understanding the changing patterns of male infertility in the world, different regions and different countries is crucial for assessing the global male fertility and reproductive health.

METHODS

We obtained data on prevalence, years of life lived with disability (YLD), age-standardized rates of prevalence (ASPR) and age-standardized YLD rate (ASYR) from the Global Burden of Disease Study 2019. We analyzed the burden of male infertility at all levels, including global, regional, national, age stratification and Socio-demographic Index (SDI).

RESULTS

In 2019, the global prevalence of male infertility was estimated to be 56,530.4 thousand (95% UI: 31,861.5-90,211.7), reflecting a substantial 76.9% increase since 1990. Furthermore, the global ASPR stood at 1,402.98 (95% UI: 792.24-2,242.45) per 100,000 population in 2019, representing a 19% increase compared to 1990. The regions with the highest ASPR and ASYR for male infertility in 2019 were Western Sub-Saharan Africa, Eastern Europe, and East Asia. Notably, the prevalence and YLD related to male infertility peaked in the 30-34 year age group worldwide. Additionally, the burden of male infertility in the High-middle SDI and Middle SDI regions exceeded the global average in terms of both ASPR and ASYR.

CONCLUSION

The global burden of male infertility has exhibited a steady increase from 1990 to 2019, as evidenced by the rising trends in ASPR and ASYR, particularly in the High-middle and Middle SDI regions. Notably, the burden of male infertility in these regions far exceeds the global average. Additionally, since 2010, there has been a notable upward trend in the burden of male infertility in Low and Middle-low SDI regions. Given these findings, it is imperative to prioritize efforts aimed at improving male fertility and reproductive health.

Sialylation: fate decision of mammalian sperm development, fertilization, and male fertility†

Sperm development, maturation, and successful fertilization within the female reproductive tract are intricate and orderly processes that involve protein translation and post-translational modifications. Among these modifications, sialylation plays a crucial role. Any disruptions occurring throughout the sperm's life cycle can result in male infertility, yet our current understanding of this process remains limited. Conventional semen analysis often fails to diagnose some infertility cases associated with sperm sialylation, emphasizing the need to comprehend and investigate the characteristics of sperm sialylation. This review reanalyzes the significance of sialylation in sperm development and fertilization and evaluates the impact of sialylation damage on male fertility under pathological conditions. Sialylation serves a vital role in the life journey of sperm, providing a negatively charged glycocalyx and enriching the molecular structure of the sperm surface, which is beneficial to sperm reversible recognition and immune interaction. These characteristics are particularly crucial during sperm maturation and fertilization within the female reproductive tract. Moreover, enhancing the understanding of the mechanism underlying sperm sialylation can promote the development of relevant clinical indicators for infertility detection and treatment.

Local Immune Biomarker Expression Depending on the Uterine Microbiota in Patients with Idiopathic Infertility

The endometrium has traditionally been considered sterile. Nowadays, active studies are performed on the female upper genital tract microbiota. Bacteria and/or viruses colonizing the endometrium are known to alter its functional properties, including receptivity and embryo implantation. Uterine cavity inflammation caused by microorganisms leads to disrupted cytokine expression, which, in turn, is mandatory for the successful implantation of the embryo. The present study assessed the vaginal and endometrial microbiota composition and its relation to the levels of cytokines produced by the endometrium in reproductive-aged women complaining of secondary infertility of unknown origin. The multiplex real-time PCR assay was applied for vaginal and endometrial microbiota analysis. The quantitative measurement of endometrial α-defensin (DEFa1), transforming growth factor (TGFβ1), and basic fibroblast growth factor (bFGF2) was carried out using the ELISA (Cloud-Clone Corporation (Katy, TX, USA; manufactured in Wuhan, China). A reliable decline in endometrial TGFβ1 and bFGF2 and an increase in DEFa1 were demonstrated in women with idiopathic infertility when compared to fertile patients. However, TGFβ1, bFGF2, and DEFa1 expression correlated reliably only with the presence of Peptostreptococcus spp. and HPV in the uterine cavity. The obtained results highlight the importance of local immune biomarker determination in the assessment of certain bacteria and viruses' significance as causative agents of infertility.

Deciphering the Function of New Therapeutic Targets and Prospective Biomarkers in the Management of Psoriasis

Psoriasis is an immune-mediated skin condition affecting people worldwide, presenting at any age, and leading to a substantial burden physically and mentally. The innate and adaptive immune systems interact intricately with the pathomechanisms that underlie disease. T cells can interact with keratinocytes, macrophages, and dendritic cells through the cytokines they secrete. According to recent research, psoriasis flare-ups can cause systemic inflammation and various other co-morbidities, including depression, psoriatic arthritis, and cardio-metabolic syndrome. Additionally, several auto-inflammatory and auto-immune illnesses may be linked to psoriasis. Although psoriasis has no proven treatment, care must strive by treating patients as soon as the disease surfaces, finding and preventing concurrent multimorbidity, recognising and reducing bodily and psychological distress, requiring behavioural modifications, and treating each patient individually. Biomarkers are traits that are assessed at any time along the clinical continuum, from the early stages of a disease through the beginning of treatment (the foundation of precision medicine) to the late stages of treatment (outcomes and endpoints). Systemic therapies that are frequently used to treat psoriasis provide a variety of outcomes. Targeted therapy selection, better patient outcomes, and more cost-effective healthcare would be made possible by biomarkers that reliably predict effectiveness and safety. This review is an attempt to understand the role of Antimicrobial peptides (AMP), Interleukin-38 (IL-38), autophagy 5 (ATG5) protein and squamous cell carcinoma antigen (SCCA) as biomarkers of psoriasis.