The mammalian testis possesses a special immunological environment because of its properties of remarkable immune privilege and effective local innate immunity. Testicular immune privilege protects immunogenic germ cells from systemic immune attack, and local innate immunity is important in preventing testicular microbial infections. The breakdown of local testicular immune homeostasis may lead to orchitis, an etiological factor of male infertility. The mechanisms underlying testicular immune privilege have been investigated for a long time. Increasing evidence shows that both a local immunosuppressive milieu and systemic immune tolerance are involved in maintaining testicular immune privilege status. The mechanisms underlying testicular innate immunity are emerging based on the investigation of the pattern recognition receptor-mediated innate immune response in testicular cells. This review summarizes our current understanding of testicular defense mechanisms and identifies topics that merit further investigation.

Our study demonstrated that MCT was efficacious in suppressing body fat accumulation, insulin resistance, inflammatory response, and NF-κB and p38 MAPK activation in high fat diet-fed mice. These data suggest that MCT may exert beneficial effects against high fat diet-induced insulin resistance and inflammation.

Glycyrrhiza glabra (licorice) has been known to possess various pharmacological properties including anti-inflammatory, antioxidants, antiviral, and hepatoprotective activities. Magnesium isoglycyrrhizinate (MgIG), a magnesium salt of 18-α glycyrrhizic acid stereoisomer, is clinically used for the treatment of inflammatory liver diseases. However, the mechanism by which MgIG exerts its anti-inflammatory effects remains unknown. In the present study, we investigated the inhibitory potential of MgIG in phospholipase A2 (PLA2)/arachidonic acid (AA) pathway and release of the pathway-generated inflammatory lipid mediators in RAW264.7 macrophages. Results revealed that MgIG suppressed LPS-induced activation of PLA2 and production of AA metabolites such as prostaglandin E2 (PGE2), prostacyclin (PGI2), thromboxane 2 (TXB2), and leukotrienes (LTB4) in macrophages. Furthermore, LPS-induced AA-metabolizing enzymes including COX-2, COX-1, 5-LOX, TXB synthase, and PGI2 synthase were significantly inhibited by MgIG. Taken together, our data suggest that modulation of cyclooxygenase (COXs) and 5-lipoxygenase (LOX) pathways in AA metabolism could be a novel mechanism for the anti-inflammatory effects of MgIG.

Cyanidin-3-O-glucoside (C3G), an anthocyanin belonging to the flavonoid family and commonly present in food and vegetables in human diet, has exhibited anti-inflammatory and anti-oxidant effects. This study aimed to investigate the protective ability of C3G against inflammatory and oxidative injuries, as well as to clarify the possible mechanism in lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVECs) in vitro and acute respiratory distress syndrome mouse model in vivo. HUVECs or male Kunming mice were pretreated with C3G 1 h before LPS stimulation. C3G significantly inhibited the production of pro-inflammatory cytokines (tumor necrosis factor-α, interleukin (IL) -6, and IL-1β) in cell supernatants and bronchoalveolar lavage fluid (BALF) as determined by enzyme-linked immunosorbent assay. Histopathologic examination with hematoxylin and eosinstaining showed that C3G pretreatment substantially suppressed inflammatory cell infiltration, alveolar wall thickening, and interstitial edemain lung tissues. C3G markedly prevented LPS-induced elevation of malondialdehyde and myeloperoxidase levels in lung tissue homogenates, wet to dry ratio of lung tissues, total cells, and inflammatory cells (neutrophils and macrophages) in BALF. Moreover, C3G reduced superoxide dismutase activity in the lung tissue homogenates. Western blot assay also showed that C3G pretreatment significantly suppressed LPS-induced activation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways by blocking the phosphorylation of inhibitor κB-α, NF-κB/P65, extracellular signal-regulated kinase, p38, and c-Jun NH2-terminal kinase in the lung tissues. In summary, C3G may ameliorate LPS-induced injury, which results from inflammation and oxidation, by inhibiting NF-κB and MAPK pathways and playing important anti-inflammatory and anti-oxidative roles.

Although wide range of viruses can infect adipose tissues, innate antiviral response of adipose cells has not been investigated. This study focused on innate antiviral system in mouse adipose cells. Major virus sensors including Toll-like receptor 3 (TLR3), melanoma differentiation-associated antigen 5 (MDA5) and retinoic acid-inducible gene I (RIG-I) are constitutively expressed in preadipocytes and adipocytes. Poly(I:C), a common agonist of TLR3, MDA5 and RIG-I, induced the expression of type I interferons (IFN-α/β) in the two types of adipose cells through the activation of IFN-regulatory factor 3 and upregulated pro-inflammatory factors such as TNF-α and IL-6 through the activation nuclear factor kappa B. Moreover, poly(I:C) induced multiple antiviral proteins including IFN-stimulating gene 15, 2'5'-oligoadenylate synthetase and Mx GTPase 1 in preadipocytes and adipocytes. The poly(I:C)-induced innate antiviral response was reduced by TLR3 deficiency and knockdown of MDA5 or RIG-I. Poly(I:C) also inhibited the differentiation of preadipocytes to adipocytes and suppressed the expression of leptin, adiponectin and resistin in mature adipocytes. The results demonstrated that adipose cells are equipped with innate antiviral system, which may modulate the function of adipocytes.

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The testis is an immune privileged organ in which the tissue-specific cells have adopted effective innate immune functions against microbial pathogens. Toll-like receptors (TLRs) mediate innate immune response in the testis. The current study demonstrates that melanoma differentiation-associated protein 5 (MDA5) and retinoic acid-inducible gene I (RIG-I) initiate the testicular innate antiviral response. Both MDA5 and RIG-I are expressed in Leydig cells, and MDA5 is also expressed in spermatids. Polyinosinic-polycytidylic acid [poly(I:C)], a common agonist of MDA5 and RIG-I, significantly induces the expression of type I interferons (IFN-α/β) and antiviral proteins, including IFN-stimulated gene 15, 2'5'-oligoadenylate synthetase 1, and Mx GTPase 1, in primary TLR3-deficient (TLR3(-/-)) Leydig and germ cells. Moreover, major proinflammatory cytokines, including TNF-α and IL-6, are significantly up-regulated by poly(I:C) in these testicular cells. The poly(I:C)-induced innate antiviral response in the testicular cells is significantly reduced by knockdown of individual MDA5 and RIG-I using specific small interfering RNA. We also provide evidence that local injection of poly(I:C) induces antiviral response in the testis of TLR3(-/-) mice. These data provide novel insights into the mechanisms underlying testicular antiviral response.

The aim of this study is to analyze whether melatonin administration influenced the nuclear factor-kappa B (NF-κB) activity, proinflammatory cytokines expression, and oxidative response in the basilar artery after SAH. A total of 48 rabbits were randomly divided into four groups: control group, SAH group, SAH + vehicle group, and SAH + melatonin group. All SAH animals were subjected to injection of autologous blood into cisterna magna twice on day 0 and day 2. The melatonin was administered intraperitoneally at a dose of 5 mg/kg/12 h simultaneously with SAH from day 0 to day 5. The basilar arteries were extracted on day 5 after SAH. As a result, we found that vascular inflammation and oxidative stress were induced in all SAH animals. In animals given melatonin, basilar arterial NF-κB and pro-inflammatory cytokines were decreased in comparison to vehicle-treated animals. Measures of oxidative stress also showed significant downregulation after melatonin treatment. Furthermore, administration of melatonin prevented vasospasm on day 5 following SAH. In conclusion, post-SAH melatonin administration may attenuate inflammatory response and oxidative stress in the spasmodic artery, and this may be one mechanism involved in the therapeutic effect of melatonin on the subsequent vasospasm after SAH.