The biology of interleukin-1: emerging concepts in the regulation of the actin cytoskeleton and cell junction dynamics

Bibliometric and visual analysis of blood-testis barrier research

Background: Extensive research on the blood-testis barrier has been undertaken in recent years. However, no systematic bibliometric study has been conducted on this subject. Our research aimed to identify the hotspots and frontiers of blood-testis barrier research and to serve as a guide for future scientific research and decision-making in the field.

Methods: Studies on the blood-testis barrier were found in the Web of Science Core Collection. VOSviewer, CiteSpace, and Microsoft Excel were used to conduct the bibliometric and visual analyses.

Results: We found 942 blood-testis barrier studies published in English between 1992 and 2022. The number of annual publications and citations increased significantly between 2011 and 2022, notably in the United States. China and the United States, the US Population Council, Endocrinology, and Cheng C. Yan were the most productive countries, institution, journal, and author, respectively. The study keywords indicated that blood-testis barrier research involves a variety of compositional features (tight junctions, cytoskeleton, adherens junctions), cell types (Sertoli cells, germ cells, Leydig cells, stem cells), reproductive toxicity (cadmium, nanoparticles, bisphenol-a), and relevant mechanisms (spermatogenesis, apoptosis, oxidative stress, dynamics, inflammation, immune privilege).

Conclusion: The composition and molecular processes of the blood-testis barrier as well as the blood-testis barrier in male infertility patients are the primary research hotspots in this field. In addition, future research will likely focus on treatment and the development of novel medications that target signal pathways in oxidative stress and apoptosis to preserve the blood-testis barrier. Further studies must extend to clinical diagnosis and therapy.

Expression of Hormones, Cytokines, and Antioxidants in Heat-Stressed Subfertile Female Dromedaries

Simple Summary

Heat stress imposes a high burden on domestic animals’ productive and reproductive performance. Due to the long hot summer, drought, and shortage of green fodders, camels raised in the desert suffer a lot of reproductive inefficiencies. This animal represents one of the main wealth sources for the desert inhabitants. Several fertility disorders have been discovered, leading to frequent breeding without pregnancy. This study aimed at exploring blood metabolites such as metabolic and reproductive hormones, cytokines, and antioxidants to be monitored as bio-indictors for subfertility in female camels. The results confirmed that none of the tested metabolic hormones and glucose revealed differences among fertile and subfertile females. However, FSH, inhibin, IL-ß, nitrous oxide, and glutathione revealed remarkable differences between fertile and subfertile females, which would be reliable tools to predict subfertility statuses in this animal. IL-ß revealed higher levels in the cases with genital inflammations. The normal profiles in control females revealed the highest FSH, and the lowest inhibin were vice versa in all subfertile females. Nonetheless, nitrous oxide and glutathione would also be reliable bio-indicators for judging the fertility status.

Abstract

The prevailing hot climate imposes heavy burdens on the productivity of the camel, goat, and sheep herds raised in the Gulf desert. Due to the lack of a reliable indicator for the various subfertility statuses in camel females, this study aimed to investigate the expression of inhibin, TGFά, ILß, FSH, sex and metabolic hormones, and antioxidants for the fertility status in camel females. Eighty-two subfertile and five fertile females were admitted to the university clinic with the complaint of repeat breeding with failed conception. The animal’s genital tracts were examined for reproductive soundness. Blood samples were withdrawn for hormonal, cytokines, and antioxidants determinations. Subfertile females were categorized into six groups; endometritis (EN, 28), inactive ovaries (IO, 20), ovarian hydrobursitis (BU, 19), vaginal adhesions (VA, 7), salpingitis (SA, 4), and cervicitis (CE, 4). Results revealed a significant increase in inhibin in all groups compared to control (68.2, 66.4, 61.8. 58.8, 58.3, 55.8, and 36 pg/mL, in CE, VA, IO, BU, EN, SA, and CON, respectively). TGFά, dehydroepiandrosterone (DHEA), and progesterone were not different among groups, whereas IL-ß differed among groups. FSH, estradiol, nitrous oxide, and glutathione were higher in CON compared with other groups. In conclusion, reproductive failures in camel females are reflected in the imbalances of endocrine, cytokines, and antioxidants bio-indicators.

Changes in Blood Cell Deformability in Chorea-Acanthocytosis and Effects of Treatment With Dasatinib or Lithium

Misshaped red blood cells (RBCs), characterized by thorn-like protrusions known as acanthocytes, are a key diagnostic feature in Chorea-Acanthocytosis (ChAc), a rare neurodegenerative disorder. The altered RBC morphology likely influences their biomechanical properties which are crucial for the cells to pass the microvasculature. Here, we investigated blood cell deformability of five ChAc patients compared to healthy controls during up to 1-year individual off-label treatment with the tyrosine kinase inhibitor dasatinib or several weeks with lithium. Measurements with two microfluidic techniques allowed us to assess RBC deformability under different shear stresses. Furthermore, we characterized leukocyte stiffness at high shear stresses. The results showed that blood cell deformability–including both RBCs and leukocytes - in general was altered in ChAc patients compared to healthy donors. Therefore, this study shows for the first time an impairment of leukocyte properties in ChAc. During treatment with dasatinib or lithium, we observed alterations in RBC deformability and a stiffness increase for leukocytes. The hematological phenotype of ChAc patients hinted at a reorganization of the cytoskeleton in blood cells which partly explains the altered mechanical properties observed here. These findings highlight the need for a systematic assessment of the contribution of impaired blood cell mechanics to the clinical manifestation of ChAc.

Role of Interleukin-1 in the pathogenesis of colorectal cancer: A brief look at anakinra therapy

Colorectal cancer (CRC) is known as one of the deadliest and most common cancers globally and causes nearly one million cancer deaths yearly. Like many malignancies, the immune system and its components play a crucial role in the pathogenesis of CRC. As multifunction mediators of the immune system, cytokines are involved in several inflammatory and anti-inflammatory responses. Interleukin-1 (IL-1) belongs to a family of 11 members and is involved in inflammatory responses. Beyond its biological role as a mediator of innate immune responses, it is also seen in chronic stress and inflammation and numerous pathological states. The role of IL-1 in malignancies can also be very significant because it has recently been shown that this cytokine can also be secreted from tumor cells and induce the recruitment of myeloid-derived immunosuppressive cells. As a result, the tumor microenvironment (TME) is affected and, despite being inflammatory, causes the onset and progression of tumor cells. Since surgery and chemotherapy are the first choices to treat patients with cancer, especially CRC, it is usually not well-prognosed, particularly in patients with metastatic lesions CRC. Therefore, targeted therapy may prolong the overall survival of CRC patients. Furthermore, evidence shows that anakinra has had satisfactory results in treating CRC. Therefore, this review summarized the role of IL-1 in the pathogenesis of CRC as well as immunotherapy based on inhibition of this cytokine in this type of cancer.

Intestinal microbe-dependent ω3 lipid metabolite αKetoA prevents inflammatory diseases in mice and cynomolgus macaques

Dietary ω3 fatty acids have important health benefits and exert their potent bioactivity through conversion to lipid mediators. Here, we demonstrate that microbiota play an essential role in the body's use of dietary lipids for the control of inflammatory diseases. We found that amounts of 10-hydroxy-cis-12-cis-15-octadecadienoic acid (αHYA) and 10-oxo-cis-12-cis-15-octadecadienoic acid (αKetoA) increased in the feces and serum of specific-pathogen-free, but not germ-free, mice when they were maintained on a linseed oil diet, which is high in α-linolenic acid. Intake of αKetoA, but not αHYA, exerted anti-inflammatory properties through a peroxisome proliferator-activated receptor (PPAR)γ-dependent pathway and ameliorated hapten-induced contact hypersensitivity by inhibiting the development of inducible skin-associated lymphoid tissue through suppression of chemokine secretion from macrophages and inhibition of NF-κB activation in mice and cynomolgus macaques. Administering αKetoA also improved diabetic glucose intolerance by inhibiting adipose tissue inflammation and fibrosis through decreased macrophage infiltration in adipose tissues and altering macrophage M1/M2 polarization in mice fed a high-fat diet. These results collectively indicate that αKetoA is a novel postbiotic derived from α-linolenic acid, which controls macrophage-associated inflammatory diseases and may have potential for developing therapeutic drugs as well as probiotic food products.

Articular Chondrocyte Phenotype Regulation through the Cytoskeleton and the Signaling Processes That Originate from or Converge on the Cytoskeleton: Towards a Novel Understanding of the Intersection between Actin Dynamics and Chondrogenic Function

Numerous studies have assembled a complex picture, in which extracellular stimuli and intracellular signaling pathways modulate the chondrocyte phenotype. Because many diseases are mechanobiology-related, this review asked to what extent phenotype regulators control chondrocyte function through the cytoskeleton and cytoskeleton-regulating signaling processes. Such information would generate leverage for advanced articular cartilage repair. Serial passaging, pro-inflammatory cytokine signaling (TNF-α, IL-1α, IL-1β, IL-6, and IL-8), growth factors (TGF-α), and osteoarthritis not only induce dedifferentiation but also converge on RhoA/ROCK/Rac1/mDia1/mDia2/Cdc42 to promote actin polymerization/crosslinking for stress fiber (SF) formation. SF formation takes center stage in phenotype control, as both SF formation and SOX9 phosphorylation for COL2 expression are ROCK activity-dependent. Explaining how it is molecularly possible that dedifferentiation induces low COL2 expression but high SF formation, this review theorized that, in chondrocyte SOX9, phosphorylation by ROCK might effectively be sidelined in favor of other SF-promoting ROCK substrates, based on a differential ROCK affinity. In turn, actin depolymerization for redifferentiation would “free-up” ROCK to increase COL2 expression. Moreover, the actin cytoskeleton regulates COL1 expression, modulates COL2/aggrecan fragment generation, and mediates a fibrogenic/catabolic expression profile, highlighting that actin dynamics-regulating processes decisively control the chondrocyte phenotype. This suggests modulating the balance between actin polymerization/depolymerization for therapeutically controlling the chondrocyte phenotype.

Interleukin-1β Modulation of the Mechanobiology of Primary Human Pulmonary Fibroblasts: Potential Implications in Lung Repair

Pro-inflammatory cytokines like interleukin-1β (IL-1β) are upregulated during early responses to tissue damage and are expected to transiently compromise the mechanical microenvironment. Fibroblasts are key regulators of tissue mechanics in the lungs and other organs. However, the effects of IL-1β on fibroblast mechanics and functions remain unclear. Here we treated human pulmonary fibroblasts from control donors with IL-1β and used Atomic Force Microscopy to unveil that IL-1β significantly reduces the stiffness of fibroblasts concomitantly with a downregulation of filamentous actin (F-actin) and alpha-smooth muscle (α-SMA). Likewise, COL1A1 mRNA was reduced, whereas that of collagenases MMP1 and MMP2 were upregulated, favoring a reduction of type-I collagen. These mechanobiology changes were functionally associated with reduced proliferation and enhanced migration upon IL-1β stimulation, which could facilitate lung repair by drawing fibroblasts to sites of tissue damage. Our observations reveal that IL-1β may reduce local tissue rigidity by acting both intracellularly and extracellularly through the downregulation of fibroblast contractility and type I collagen deposition, respectively. These IL-1β-dependent mechanical effects may enhance lung repair further by locally increasing pulmonary tissue compliance to preserve normal lung distension and function. Moreover, our results support that IL-1β provides innate anti-fibrotic protection that may be relevant during the early stages of lung repair.

Immune genes, IL1β and Casp9, show sexual dimorphic methylation patterns in zebrafish gonads

There is crosstalk between the immune and reproductive systems in which sexual dimorphism is a common pattern in vertebrates. In recent years, epigenetics has emerged as a way to study the molecular mechanisms involved in gonadal development, those responsible for integrating environmental information that contribute to assigning a specific sexual phenotype (either an ovary or a testis). The knowledge of epigenetic mechanisms in certain molecular processes allows the development of epigenetic markers. In fish gonads, the existence of reproduction-immune system interactions is known, although the epigenetic mechanisms involved are far from clear. Here, we used the zebrafish (Danio rerio) as a model to study the DNA methylation patterns in gonads of two well-known innate immune genes: IL1β and Casp9. DNA methylation levels were studied by a candidate gene approach at single nucleotide resolution and gene expression analyses were also carried out. Results showed that there was clear sexual dimorphism in the DNA methylation levels of the two immune genes studied, being significantly higher in the testes when compared to the ovaries. In summary, and although further research is needed, this paper presents sexual dimorphic methylation patterns of two immune-related genes, thus sex-biased differences in methylation profiles should considered when analyzing immune responses in fish. Data showed here can help to develop epimarkers with forthcoming applications in livestock and fish farming production, for example, in immune fish diseases or sexual control programs as epigenetic molecular tools to predict environmental pressure in the gonads.

Effects of human cyclooxygenase-2 gene silencing on synovial cells of rheumatoid arthritis mediated by lentivirus

The aim of the study is to screen the effective shRNA sequence which can silence the human COX-2 expression level in synovial cells of rheumatoid arthritis (RA) patient transfected by the lentivirus. Four pairs of hCOX-2 shRNA were designed and inserted into lentivirus to form pGPHI/GFP/Neo-shRNA vector. The reconstructed virus was transfected into synovial cells derived from RA patients, and then the expression level of hCOX-2 mRNA and the protein of the inflammatory factors including prostaglandin E2 (PGE2), vascular endothelial growth factor (VEGF), interleukin-1β (IL-1β) and tumour necrosis factor alpha (TNF-α) in the supernatants were examined with real-time PCR and ELISA, respectively. There was no obvious negative influence on cell growth and morphology after hCOX-2 shRNA gene transfection mediated by lentivirus. The hCOX-2 mRNA expression level, as well as the concentration of PGE2, VEGF, IL-1β and TNF-α, decreased significantly (p < .05). RNAi mediated by lentivirus can significantly inhibit hCOX-2 mRNA expression level in synovial cells of RA patients, so as to reduce the expression of inflammatory cytokines.

FAM13A is a modifier gene of cystic fibrosis lung phenotype regulating rhoa activity, actin cytoskeleton dynamics and epithelial-mesenchymal transition

BACKGROUND

Cystic fibrosis (CF) lung disease severity is highly variable and dependent on several factors including genetic modifiers. Family with sequence similarity 13 member A (FAM13A) has been previously associated with lung function in the general population as well as in several chronic lung diseases, such as chronic obstructive pulmonary disease (COPD), we examined whether FAM13A is a modifier gene of CF lung phenotype. We also studied how FAM13A may contribute to the physiopathological mechanisms associated with CF.

METHODS

We investigated the association of FAM13A with lung function in CF French patients (n=1222) by SNP-wise analysis and Versatile Gene Based Association Study. We also analyzed the consequences of FAM13A knockdown in A549 cells and primary bronchial epithelial cells from CF patients.

RESULTS

We found that FAM13A is associated with lung function in CF patients. Utilizing lung epithelial A549 cells and primary human bronchial epithelial cells from CF patients we observed that IL-1β and TGFβ reduced FAM13A expression. Knockdown of FAM13A was associated with increased RhoA activity, induction of F-actin stress fibers and regulation of epithelial-mesenchymal transition markers such as E-cadherin, α-smooth muscle actin and vimentin.

CONCLUSION

Our data show that FAM13A is a modifier gene of CF lung phenotype regulating RhoA activity, actin cytoskeleton dynamics and epithelial-mesenchymal transition.

From the Cover: An Animal-Free In Vitro Three-Dimensional Testicular Cell Coculture Model for Evaluating Male Reproductive Toxicants

Primary testicular cell coculture model has been used to evaluate testicular abnormalities during development, and was able to identify the testicular toxicity of phthalates. However, the primary testicular cell coculture model has disadvantages in employing animals for the isolation of testicular cells, and the complicated isolation procedure leads to inconsistent results. We developed an invitro testicular coculture model from rodent testicular cell lines, including spermatogonial cells, Sertoli cells, and Leydig cells with specified cell density and extracellular matrix (ECM) composition. Using comparative high-content analysis of F-actin cytoskeletal structure between the coculture and single cell culture models, we demonstrated a 3D structure of the coculture, which created an invivo-like niche, and maintained and supported germ cells within a 3D environment. We validated this model by discriminating between reproductive toxicants and nontoxicants among 32 compounds in comparison to the single cell culture models. Furthermore, we conducted a comparison between the invitro (IC50) and invivo reproductive toxicity testing (lowest observed adverse effect level on reproductive system). We found the invitro coculture model could classify the tested compounds into 4 clusters, and identify the most toxic reproductive substances, with high concordance, sensitivity, and specificity of 84%, 86.21%, and 100%, respectively. We observed a strong correlation of IC50 between the invitro coculture model and the invivo testing results. Our results suggest that this novel invitro coculture model may be useful for screening testicular toxicants and prioritize chemicals for further assessment in the future.

Celastrol inhibits IL-1β-induced inflammation in orbital fibroblasts through the suppression of NF-κB activity

Graves' disease is an autoimmune disease of the thyroid gland, which is characterized by hyperthyroidism, diffuse goiter and Graves' ophthalmopathy (GO). Although several therapeutic strategies for the treatment of GO have been developed, the effectiveness and the safety profile of these therapies remain to be fully elucidated. Therefore, examination of novel GO therapies remains an urgent requirement. Celastrol, a triterpenoid isolated from traditional Chinese medicine, is a promising drug for the treatment of various inflammatory and autoimmune diseases. CCK‑8 and apoptosis assays were performed to investigate cytotoxicity of celastrol and effect on apoptosis on orbital fibroblasts. Reverse transcription‑polymerase chain reaction, western blotting and ELISAs were performed to examine the effect of celastrol on interleukin (IL)‑1β‑induced inflammation in orbital fibroblasts from patients with GO. The results demonstrated that celastrol significantly attenuated the expression of IL‑6, IL‑8, cyclooxygenase (COX)‑2 and intercellular adhesion molecule‑1 (ICAM‑1), and inhibited IL‑1β‑induced increases in the expression of IL‑6, IL‑8, ICAM‑1 and COX‑2. The levels of prostaglandin E2 in orbital fibroblasts induced by IL‑1β were also suppressed by celastrol. Further investigation revealed that celastrol suppressed the IL‑1β‑induced inflammatory responses in orbital fibroblasts through inhibiting the activation of nuclear factor (NF)‑κB. Taken together, these results suggested that celastrol attenuated the IL‑1β‑induced pro‑inflammatory pathway in orbital fibroblasts from patients with GO, which was associated with the suppression of NF-κB activation.

Regulation of the blood-testis barrier

The purpose of this review is to describe the endocrine and local testicular factors that contribute to the regulation of the blood-testis barrier (BTB), using information gained from in vivo and in vitro models of BTB formation during/after puberty, and from the maintenance of BTB function during adulthood. In vivo the BTB, in part comprised of tight junctions between adjacent somatic Sertoli cells, compartmentalizes meiotic spermatocytes and post-meiotic spermatids away from the vasculature, and therefore prevents autoantibody production by the immune system against these immunogenic germ cells. This adluminal compartment also features a unique biochemical milieu required for the completion of germ cell development. During the normal process of spermatogenesis, earlier germ cells continually cross into the adluminal compartment, but the regulatory mechanisms and changes in junctional proteins that allow this translocation step without causing a 'leak' remain poorly understood. Recent data describing the roles of FSH and androgen on the regulation of Sertoli cell tight junctions and tight junction proteins will be discussed, followed by an examination of the role of paracrine factors, including members of the TGFβ superfamily (TGFβ3, activin A) and retinoid signalling, as potential mediators of junction assembly and disassembly during the translocation process.

Axis of immune response and energy metabolism mediated by Notch/mTOR signaling pathway: Pivotal mechanism of traditional Chinese medicine for preventing inflammatory bowel disease

Inflammatory bowel disease (IBD) is a kind of worldwide refractory disease with a high recurrence rate. However, traditional Chinese medicine for IBD is associated with a better therapeutic effect and a lower recurrence rate, although the mechanism is still unclear. It is known that the Notch signaling pathway interacts with mTOR and regulates the body's immune level and cell energy, which is closely related with morbidity of IBD. These hint that axis of immune response and energy metabolism mediated by the Notch/mTOR signaling pathway is possibly a pivotal mechanism for traditional Chinese medicine to prevent IBD.

Selective IL-1α exposure to the fetal gut, lung, and chorioamnion/skin causes intestinal inflammatory and developmental changes in fetal sheep

Chorioamnionitis, caused by intra-amniotic exposure to bacteria and their toxic components, is associated with fetal gut inflammation and mucosal injury. In a translational ovine model, we have shown that these adverse intestinal outcomes to chorioamnionitis were the combined result of local gut and pulmonary-driven systemic immune responses. Chorioamnionitis-induced gut inflammation and injury was largely prevented by inhibiting interleukin-1 (IL-1) signaling. Therefore, we investigated whether local (gut-derived) IL-1α signaling or systemic IL-1α-driven immune responses (lung or chorioamnion/skin-derived) were sufficient for intestinal inflammation and mucosal injury in the course of chorioamnionitis. Fetal surgery was performed in sheep to isolate the lung, gastrointestinal tract, and chorioamnion/skin, and IL-1α or saline was given into the trachea, stomach, or amniotic cavity 1 or 6 days before preterm delivery. Selective IL-1α exposure to the lung, gut, or chorioamnion/skin increased the CD3+ cell numbers in the fetal gut. Direct IL-1α exposure to the gut impaired intestinal zonula occludens protein-1 expression, induced villus atrophy, changed the expression pattern of intestinal fatty acid-binding protein along the villus, and increased the CD68, IL-1, and TNF-α mRNA levels in the fetal ileum. With lung or chorioamnion/skin exposure to IL-1α, intestinal inflammation was associated with increased numbers of blood leukocytes without induction of intestinal injury or immaturity. We concluded that local IL-1α signaling was required for intestinal inflammation, disturbed gut maturation, and mucosal injury in the context of chorioamnionitis.

Transcriptional analysis identifies key genes involved in metabolism, fibrosis/tissue repair and the immune response against Fasciola hepatica in sheep liver

BACKGROUND

Although fascioliasis has been relatively well studied, little is known about the molecular basis of this disease. This is particularly relevant, considering the very different response that sheep have to Fasciola hepatica relative to cattle. The acute phase of this disease is severe in sheep, whereas chronic fascioliasis is more common in cattle.

METHODS

To begin to explore the host-response to Fasciola in sheep and improve the understanding of the host-pathogen interactions during the parasite's migration through liver parenchyma to the bile duct, we used RNA sequencing (RNA-seq) to investigate livers from sheep infected for eight weeks compared with those from uninfected controls.

RESULTS

This study identified 572 and 42 genes that were up- and down-regulated, respectively, in infected livers relative to uninfected controls. Our molecular findings provide significant new insights into the mechanisms linked to metabolism, fibrosis and tissue-repair in sheep, and highlight the relative importance of specific components of immune response pathways, which appear to be driven toward a suppression of inflammation.

CONCLUSIONS

This study is, to our knowledge, the first detailed investigation of the transcriptomic responses in the liver tissue of any host to F. hepatica infection. It defines the involvement of specific genes associated with the host's metabolism, immune response and tissue repair/regeneration, and highlights an apparent overlapping function of many genes involved in these processes.

Pirfenidone attenuates IL-1β-induced COX-2 and PGE2 production in orbital fibroblasts through suppression of NF-κB activity

The aim of this study was to determine the effect of pirfenidone on interleukin (IL)-1β-induced cyclooxygenase (COX)-2 and prostaglandin (PG)E2 expression in orbital fibroblasts from patients with thyroid-associated ophthalmopathy (TAO). Primary cultures of orbital fibroblasts from patients with TAO (n = 4) and non-TAO subjects (n = 4) were prepared. The level of PGE2 in orbital fibroblasts treated with IL-1β in the presence or absence of pirfenidone was measured using an enzyme-linked immunosorbent assay. The effect of pirfenidone on IL-1β-induced COX-2 expression in orbital fibroblasts from patients with TAO was evaluated by reverse transcription-polymerase chain reaction (PCR) and quantitative real-time PCR analyses, and verified by Western blot. Activation of nuclear factor-κB (NF-κB) was evaluated by immunoblotting for inhibitor of κB (IκB)α and phosphorylated IκBα, and DNA-binding activity of p50/p65 NF-κB was analyzed by electrophoretic mobility shift assay. In addition, IL-1 receptor type 1 (IL-1R1) expression was assessed by RT-PCR in IL-1β-treated cells with or without pirfenidone. Pirfenidone significantly attenuated IL-1β-induced PGE2 release in both TAO and non-TAO cells. IL-1β-induced COX-2 mRNA and protein expression decreased significantly following co-treatment with pirfenidone. IL-1β-induced IκBα phosphorylation and degradation decreased in the presence of pirfenidone and led to decreased nuclear translocation and DNA binding of the active NF-κB complex. In our system, neither IL-1β nor pirfenidone co-treatment influenced IL-1R1 expression. Our results suggest that pirfenidone attenuates the IL-1β-induced PGE2/COX-2 production in TAO orbital fibroblasts, which is related with suppression of the NF-κB activation.

Intercellular adhesion molecules (ICAMs) and spermatogenesis

BACKGROUND

During the seminiferous epithelial cycle, restructuring takes places at the Sertoli-Sertoli and Sertoli-germ cell interface to accommodate spermatogonia/spermatogonial stem cell renewal via mitosis, cell cycle progression and meiosis, spermiogenesis and spermiation since developing germ cells, in particular spermatids, move 'up and down' the seminiferous epithelium. Furthermore, preleptotene spermatocytes differentiated from type B spermatogonia residing at the basal compartment must traverse the blood-testis barrier (BTB) to enter the adluminal compartment to prepare for meiosis at Stage VIII of the epithelial cycle, a process also accompanied by the release of sperm at spermiation. These cellular events that take place at the opposite ends of the epithelium are co-ordinated by a functional axis designated the apical ectoplasmic specialization (ES)-BTB-basement membrane. However, the regulatory molecules that co-ordinate cellular events in this axis are not known.

METHODS

Literature was searched at http://www.pubmed.org and http://scholar.google.com to identify published findings regarding intercellular adhesion molecules (ICAMs) and the regulation of this axis.

RESULTS

Members of the ICAM family, namely ICAM-1 and ICAM-2, and the biologically active soluble ICAM-1 (sICAM-1) are the likely regulatory molecules that co-ordinate these events. sICAM-1 and ICAM-1 have antagonistic effects on the Sertoli cell tight junction-permeability barrier, involved in Sertoli cell BTB restructuring, whereas ICAM-2 is restricted to the apical ES, regulating spermatid adhesion during the epithelial cycle. Studies in other epithelia/endothelia on the role of the ICAM family in regulating cell movement are discussed and this information has been evaluated and integrated into studies of these proteins in the testis to create a hypothetical model, depicting how ICAMs regulate junction restructuring events during spermatogenesis.

CONCLUSIONS

ICAMs are crucial regulatory molecules of spermatogenesis. The proposed hypothetical model serves as a framework in designing functional experiments for future studies.

Filamin A: A regulator of blood-testis barrier assembly during post-natal development

Filamins are a family of actin-binding proteins composed of filamin A, B and C. Besides of their ability to induce perpendicular branching of F-actin filaments via their actin binding domains near the N-terminus, filamins can regulate multiple cellular functions because of their unique ability to recruit more than 90 protein binding partners to their primary sequences which are having highly diversified cellular functions. However, this family of proteins has not been examined in the testis until recently. Herein, we highlight recent findings in the field regarding the role of these proteins in cell epithelia, and based on recent data in the testis regarding their role on spermatogenesis, this review provides the basis for future functional studies.

The blood-testis barrier and its implications for male contraception

The blood-testis barrier (BTB) is one of the tightest blood-tissue barriers in the mammalian body. It divides the seminiferous epithelium into the basal and the apical (adluminal) compartments. Meiosis I and II, spermiogenesis, and spermiation all take place in a specialized microenvironment behind the BTB in the apical compartment, but spermatogonial renewal and differentiation and cell cycle progression up to the preleptotene spermatocyte stage take place outside of the BTB in the basal compartment of the epithelium. However, the BTB is not a static ultrastructure. Instead, it undergoes extensive restructuring during the seminiferous epithelial cycle of spermatogenesis at stage VIII to allow the transit of preleptotene spermatocytes at the BTB. Yet the immunological barrier conferred by the BTB cannot be compromised, even transiently, during the epithelial cycle to avoid the production of antibodies against meiotic and postmeiotic germ cells. Studies have demonstrated that some unlikely partners, namely adhesion protein complexes (e.g., occludin-ZO-1, N-cadherin-β-catenin, claudin-5-ZO-1), steroids (e.g., testosterone, estradiol-17β), nonreceptor protein kinases (e.g., focal adhesion kinase, c-Src, c-Yes), polarity proteins (e.g., PAR6, Cdc42, 14-3-3), endocytic vesicle proteins (e.g., clathrin, caveolin, dynamin 2), and actin regulatory proteins (e.g., Eps8, Arp2/3 complex), are working together, apparently under the overall influence of cytokines (e.g., transforming growth factor-β3, tumor necrosis factor-α, interleukin-1α). In short, a "new" BTB is created behind spermatocytes in transit while the "old" BTB above transiting cells undergoes timely degeneration, so that the immunological barrier can be maintained while spermatocytes are traversing the BTB. We also discuss recent findings regarding the molecular mechanisms by which environmental toxicants (e.g., cadmium, bisphenol A) induce testicular injury via their initial actions at the BTB to elicit subsequent damage to germ-cell adhesion, thereby leading to germ-cell loss, reduced sperm count, and male infertility or subfertility. Moreover, we also critically evaluate findings in the field regarding studies on drug transporters in the testis and discuss how these influx and efflux pumps regulate the entry of potential nonhormonal male contraceptives to the apical compartment to exert their effects. Collectively, these findings illustrate multiple potential targets are present at the BTB for innovative contraceptive development and for better delivery of drugs to alleviate toxicant-induced reproductive dysfunction in men.