A quantitative global proteomics approach to understanding the functional pathways dysregulated in the spermatozoa of asthenozoospermic testicular cancer patients.

BACKGROUND: Testicular cancer (TC) is the most common cancer diagnosed in men of reproductive age group. Sperm banking is recommended in these patients prior to cancer treatment. There is no literature describing the proteins dysregulated in the spermatozoa of TC patients with poor motility. OBJECTIVE: The primary objective of this study was to compare the differences in the sperm proteome of normozoospermic (motility > 40%) and asthenozoospermic (motility < 40%) TC patients who had cryopreserved semen samples before initiating cancer therapy. MATERIALS AND METHODS: Pooled sperm samples from healthy fertile men (n = 8), normozoospermic (n = 20), and asthenozoospermic (n = 11) TC patients were used for quantitative global proteomic profiling by liquid chromatography-tandem mass spectrometry (LC-MS). The functional bioinformatic analysis was done by ingenuity pathway analysis software. Key differentially expressed proteins (DEPs) associated with binding of zona pellucida (CCT3), mitochondrial dysfunction (ATP5A1 and UQCRC2), sperm motility (ATP1A4), and an exosomal protein involved in the metabolic process of the spermatozoa (MMP9) were validated using Western blot analysis by comparing normozoospermic (n = 10) with asthenozoospermic (n = 10) TC patients. Statistical analysis was conducted using Mann-Whitney test. RESULTS: A total of 813 and 957 proteins were detected in spermatozoa of normozoospermic and asthenozoospermic TC patients, respectively. On the other hand, 1139 proteins were detected in the spermatozoa of healthy fertile men. 198 proteins were identified as DEPs between TC patients with normal and abnormal semen parameters. Validation of DEPs revealed downregulation of key proteins (CCT3, ATP1A4, ATP5A1, and UQCRC2) implicated in the reproductive function in asthenozoospermic TC patients. DISCUSSION: DEPs involved in the reproductive function pathways suggest defective spermatogenesis and maturation process in asthenozoospermic TC patients. Furthermore, dysfunctional exosomal pathway may be a possible cause of infertility in TC patients. CONCLUSION: The proteins associated with sperm function and fertilization process are compromised in TC patients irrespective of their semen parameters.

Dissecting the role of the S1P/S1PR axis in health and disease.

Sphingosine-1-phosphate (S1P) is a pleiotropic sphingophospholipid generated from the phosphorylation of sphingosine by sphingosine kinases (SPHKs). S1P has been experimentally demonstrated to modulate an array of cellular processes such as cell proliferation, cell survival, cell invasion, vascular maturation, and angiogenesis by binding with any of the five known G-protein-coupled sphingosine 1 phosphate receptors (S1P1-5) on the cell surface in an autocrine as well as a paracrine manner. Recent studies have shown that the S1P receptors (S1PRs) and SPHKs are the key targets for modulating the pathophysiological consequences of various debilitating diseases, such as cancer, sepsis, rheumatoid arthritis, ulcerative colitis, and other related illnesses. In this article, we recapitulate these novel discoveries relative to the S1P/S1PR axis, necessary for the proper maintenance of health, as well as the induction of tumorigenic, angiogenic, and inflammatory stimuli that are vital for the development of various diseases, and the novel therapeutic tools to modulate these responses in oral biology and medicine.

Sphingosine kinase 1 regulates the expression of proinflammatory cytokines and nitric oxide in activated microglia.

Microglial activation has been implicated as one of the causative factors for neuroinflammation in various neurodegenerative diseases. The sphingolipid metabolic pathway plays an important role in inflammation, cell proliferation, survival, chemotaxis, and immunity in peripheral macrophages. In this study, we demonstrate that sphingosine kinase1 (SphK1), a key enzyme of the sphingolipid metabolic pathway, and its receptors are expressed in the mouse BV2 microglial cells and SphK1 alters the expression and production of proinflammatory cytokines and nitric oxide in microglia treated with lipopolysaccharide (LPS). LPS treatment increased the SphK1 mRNA and protein expression in microglia as revealed by the RT-PCR, Western blot and immunofluorescence. Suppression of SphK1 by its inhibitor, N, N Dimethylsphingosine (DMS), or siRNA resulted in decreased mRNA expression of TNF-alpha, IL-1beta, and iNOS and release of TNF-alpha and nitric oxide (NO) in LPS-activated microglia. Moreover, addition of sphingosine 1 phosphate (S1P), a breakdown product of sphingolipid metabolism, increased the expression levels of TNF-alpha, IL-1beta and iNOS and production of TNF-alpha and NO in activated microglia. Hence to summarize, suppression of SphK1 in activated microglia inhibits the production of proinflammatory cytokines and NO and the addition of exogenous S1P to activated microglia enhances their inflammatory responses. Since the chronic proinflammatory cytokine production by microglia has been implicated in neuroinflammation, modulation of SphK1 and S1P in microglia could be looked upon as a future potential therapeutic method in the control of neuroinflammation in neurodegenerative diseases.

siRNA, miRNA, and shRNA: in vivo applications.

RNA interference (RNAi), an accurate and potent gene-silencing method, was first experimentally documented in 1998 in Caenorhabditis elegans by Fire et al., who subsequently were awarded the 2006 Nobel Prize in Physiology/Medicine. Subsequent RNAi studies have demonstrated the clinical potential of synthetic small interfering RNAs (siRNAs) or short hairpin RNAs (shRNAs) in dental diseases, eye diseases, cancer, metabolic diseases, neurodegenerative disorders, and other illnesses. siRNAs are generally from 21 to 25 base-pairs (bp) in length and have sequence-homology-driven gene-knockdown capability. RNAi offers researchers an effortless tool for investigating biological systems by selectively silencing genes. Key technical aspects--such as optimization of selectivity, stability, in vivo delivery, efficacy, and safety--need to be investigated before RNAi can become a successful therapeutic strategy. Nevertheless, this area shows a huge potential for the pharmaceutical industry around the globe. Interestingly, recent studies have shown that the small RNA molecules, either indigenously produced as microRNAs (miRNAs) or exogenously administered synthetic dsRNAs, could effectively activate a particular gene in a sequence-specific manner instead of silencing it. This novel, but still uncharacterized, phenomenon has been termed 'RNA activation' (RNAa). In this review, we analyze these research findings and discussed the in vivo applications of siRNAs, miRNAs, and shRNAs.