Remodeling of the plasma membrane in preparation for sperm–egg recognition: roles of acrosomal proteins

The interaction of sperm with the egg''s extracellular matrix, the zona pellucida (ZP) is the first step of the union between male and female gametes. The molecular mechanisms of this process have been studied for the past six decades with the results obtained being both interesting and confusing. In this article, we describe our recent work, which attempts to address two lines of questions from previous studies. First, because there are numerous ZP binding proteins reported by various researchers, how do these proteins act together in sperm–ZP interaction? Second, why do a number of acrosomal proteins have ZP affinity? Are they involved mainly in the initial sperm–ZP binding or rather in anchoring acrosome reacting/reacted spermatozoa to the ZP? Our studies reveal that a number of ZP binding proteins and chaperones, extracted from the anterior sperm head plasma membrane, coexist as high molecular weight (HMW) complexes, and that these complexes in capacitated spermatozoa have preferential ability to bind to the ZP. Zonadhesin (ZAN), known as an acrosomal protein with ZP affinity, is one of these proteins in the HMW complexes. Immunoprecipitation indicates that ZAN interacts with other acrosomal proteins, proacrosin/acrosin and sp32 (ACRBP), also present in the HMW complexes. Immunodetection of ZAN and proacrosin/acrosin on spermatozoa further indicates that both proteins traffic to the sperm head surface during capacitation where the sperm acrosomal matrix is still intact, and therefore they are likely involved in the initial sperm–ZP binding step.     

Nicotine and lipopolysaccharide affect cytokine expression from gingival fibroblasts

BACKGROUND: This in vitro study investigated the influence of nicotine, lipopolysaccharide (LPS), and a combination of both agents on cytokine expression from human gingival fibroblasts (HGFs). METHODS: HGFs were exposed for 48 hours to 250 microg/ml nicotine, 1 microg/ml Porphyromonas gingivalis LPS, or both. The expression of multiple cytokines was detected in the HGFs conditioned media using cytokine protein arrays. RESULTS: The untreated HGFs expressed several cytokines, which included relatively high levels of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1). They also expressed low levels of growth-regulated oncogene (GRO), IL-3, and IL-10. Nicotine had the greatest effect on the expression of GRO-alpha, IL-7, IL-10, and IL-15 compared to the untreated control. P. gingivalis LPS had the greatest effect on the expression of GRO-alpha; IL-7; IL-10; and RANTES (regulated on activation, normal T-cell expressed, and presumably secreted) compared to the untreated control. The combination of both agents had the biggest impact on the expression of GRO-alpha, IL-7, IL-10, IL-15, RANTES, and interferon-gamma (IFN-gamma) compared to the untreated control. CONCLUSION: HGFs exposed to nicotine, P. gingivalis LPS, or a combination of both agents increased the expression of multiple cytokines.     

Lipidomic Profiling of Sinus Mucosa from Patients with Chronic Rhinosinusitis

Sinusitis is a cause of significant morbidity, substantial healthcare costs, and negative effects on quality of life. The primary objective of this study is to characterize the previously unknown lipid profile of sinonasal mucosa from patients with chronic rhinosinusitis (CRS) and from controls. Sinus mucosa samples were analyzed from 9 CRS patients with concomitant nasal polyps, 11 CRS patients without polyps, and 12 controls. Ten lone polyp samples were also analyzed. Samples were subjected to a modified Bligh/Dyer lipid extraction, then high performance thin layer chromatography (HPTLC), combined gas chromatography/electron impact‐mass spectrometry (GC/EI‐MS), and flow‐injection/electrospray ionization‐tandem mass spectrometry (FI/ESI‐MS/MS). Data was analyzed for identification and profiling of major components. HPTLC revealed an array of species reflecting the lipid complexity of the samples. GC/EI‐MS revealed cholesterol and several fatty acids. FI/ESI‐MSMS revealed numerous lipid species, namely a host of phosphatidylcholines, phosphatidylethanolamines, ceramides and cholesteryl esters, but no detectable amounts of phosphatidyinositols or sulfated lipids. These results are a first step to uncover unique molecular biomarkers in CRS.     

Presence of arylsulfatase A and sulfogalactosylglycerolipid in mouse ovaries: localization to the corpus luteum

Arylsulfatase A (AS-A) is a lysosomal enzyme, which catalyzes the desulfation of certain sulfogalactolipids, including sulfogalactosylglycerolipid (SGG), a molecule implicated in cell adhesion. In this report, immunocytochemistry revealed the selective presence of AS-A in the corpus luteum of mouse ovaries. Immunoblotting indicated that mouse corpus luteum AS-A had a molecular mass of 66 kDa, similar to AS-A of other tissues. Corpus luteum AS-A was active, capable of desulfating the artificial substrate, p-nitrocatechol sulfate, at the optimum pH of five. To understand further the role of AS-A in female reproduction, levels of AS-A were determined during corpus luteum development in pseudopregnant mice and during luteolysis after cessation of pseudopregnancy. Immunocytochemistry, immunoblotting and desulfation activity showed that AS-A expression was evident at the onset of pseudopregnancy in the newly formed corpora lutea, and its level increased steadily during gland development. The increase in the expression and activity of AS-A continued throughout luteolysis after the decrease in serum progesterone levels. We also observed the selective presence of SGG on the luteal cell surface in developed corpora lutea, as shown by immunofluorescence of mouse ovary sections as well as high-performance thin-layer chromatography of lipids isolated from mouse and pig corpora lutea. The identity of the "SGG" band on the thin layer silica plate was further validated by electrospray ionization mass spectrometry. Significantly, SGG disappeared in regressing corpora lutea. Therefore, lysosomal AS-A may be involved in cell-surface remodeling during luteolysis by desulfating SGG after its endocytosis and targeting to the lysosome.     

Interactions between cavity preparation and restoration events and their effects on pulp vitality

The purpose of this study was to investigate the precise effect and rank the importance of cavity preparation and restoration variables on human pulp vitality. Fifty-three Class V unexposed cavities were prepared and restored with calcium hydroxide/amalgam, resin-modified glass ionomer, zinc oxide-eugenol, resin composite, or zinc polycarboxylate materials. Pulp vitality was reduced by the remaining dentin thickness of the cavity preparations, whereas the other variables, including the type of restorative material, had little effect. Restorative materials cause minimal pulp damage in isolation; it is more important to minimize the removal of intact dentin to maintain the vitality of teeth.