Venkatarangaiah Krishna

Proteomic analysis of human vitreous humor

BackgroundThe vitreous humor is a transparent, gelatinous mass whose main constituent is water. It plays an important role in providing metabolic nutrient requirements of the lens, coordinating eye growth and providing support to the retina. It is in close proximity to the retina and reflects many of the changes occurring in this tissue. The biochemical changes occurring in the vitreous could provide a better understanding about the pathophysiological processes that occur in vitreoretinopathy. In this study, we investigated the proteome of normal human vitreous humor using high resolution Fourier transform mass spectrometry.ResultsThe vitreous humor was subjected to multiple fractionation techniques followed by LC-MS/MS analysis. We identified 1,205 proteins, 682 of which have not been described previously in the vitreous humor. Most proteins were localized to the extracellular space (24%), cytoplasm (20%) or plasma membrane (14%). Classification based on molecular function showed that 27% had catalytic activity, 10% structural activity, 10% binding activity, 4% cell and 4% transporter activity. Categorization for biological processes showed 28% participate in metabolism, 20% in cell communication and 13% in cell growth. The data have been deposited to the ProteomeXchange with identifier PXD000957.ConclusionThis large catalog of vitreous proteins should facilitate biomedical research into pathological conditions of the eye including diabetic retinopathy, retinal detachment and cataract.

Characterizing the normal proteome of human ciliary body

BackgroundThe ciliary body is the circumferential muscular tissue located just behind the iris in the anterior chamber of the eye. It plays a pivotal role in the production of aqueous humor, maintenance of the lens zonules and accommodation by changing the shape of the crystalline lens. The ciliary body is the major target of drugs against glaucoma as its inhibition leads to a drop in intraocular pressure. A molecular study of the ciliary body could provide a better understanding about the pathophysiological processes that occur in glaucoma. Thus far, no large-scale proteomic investigation has been reported for the human ciliary body.ResultsIn this study, we have carried out an in-depth LC-MS/MS-based proteomic analysis of normal human ciliary body and have identified 2,815 proteins. We identified a number of proteins that were previously not described in the ciliary body including importin 5 (IPO5), atlastin-2 (ATL2), B-cell receptor associated protein 29 (BCAP29), basigin (BSG), calpain-1 (CAPN1), copine 6 (CPNE6), fibulin 1 (FBLN1) and galectin 1 (LGALS1). We compared the plasma proteome with the ciliary body proteome and found that the large majority of proteins in the ciliary body were also detectable in the plasma while 896 proteins were unique to the ciliary body. We also classified proteins using pathway enrichment analysis and found most of proteins associated with ubiquitin pathway, EIF2 signaling, glycolysis and gluconeogenesis.ConclusionsMore than 95% of the identified proteins have not been previously described in the ciliary body proteome. This is the largest catalogue of proteins reported thus far in the ciliary body that should provide new insights into our understanding of the factors involved in maintaining the secretion of aqueous humor. The identification of these proteins will aid in understanding various eye diseases of the anterior segment such as glaucoma and presbyopia.

In vitro antioxidant and in vivo prophylactic effects of two γ-lactones isolated from Grewia tiliaefolia against hepatotoxicity in carbon tetrachloride intoxicated rats

Grewia tiliaefolia is widely used in traditional Indian medicines to cure jaundice, biliousness, dysentery and the diseases of blood. Bioassay-guided fractionation of methanolic extract of the G. tiliaefolia bark has resulted in the isolation of D-erythro-2-hexenoic acid gamma-lactone (EHGL) and gulonic acid gamma-lactone (GAGL). Hepatoprotective activity of the methanolic extract and the isolated constituents were evaluated against CCl(4)-induced hepatotoxicity in rats. The treatment with methanolic extract, EHGL and GAGL at oral doses of 100, 150 and 60 mg/kg respectively with concomitant CCl(4) intraperitoneal injection (1 ml/kg) significantly reduced the elevated plasma levels of aminotransferases, alkaline phosphatase and the incidence of liver necrosis compared with the CCl(4)-injected group without affecting the concentrations of serum bilirubin and hepatic markers. EHGL and GAGL significantly inhibited the elevated levels of thiobarbituric acid reactive substances and glutathione in liver homogenates. Histology of the liver tissues of the extract and isolated constituents treated groups showed the presence of normal hepatic cords, absence of necrosis and fatty infiltration as similar to the normal control. The results revealed that the hepatoprotective activity of EHGL is significant as similar to the standard drug silymarin. To clarify the influence of the extract and isolated constituents on the protection of oxidative-hepatic damage, we examined in vitro antioxidant properties of the test compounds. The extract and the constituents showed significant free radical scavenging activity. These results suggest that the extract as well as the constituents could protect the hepatocytes from CCl(4)-induced liver damage perhaps, by their anti-oxidative effect on hepatocytes, hence eliminating the deleterious effects of toxic metabolites from CCl(4).

Hepatoprotective and in vitro antioxidant effect of Carthamus tinctorious L, var Annigeri-2-, an oil-yielding crop, against CCl 4 -induced liver injury in rats

Background: The present investigation evaluates the hepatoprotective and in vitro antioxidant effect of methanolic extract and its isolated constituent, dehydroabietylamine, in Carthamus tinctorious L, var Annigeri-2-, an oil yielding crop. Materials and Methods: The hepatoprotective effects were estimated for the parameters viz, total bilirubin, total protein, serum alanine amino transaminase (ALT) and serum aspartate aminotransferase (AST) and alkaline phosphatase (ALP) and along with the pathological findings of hepatotoxicity. The in vitro antioxidant activity was evaluated by using free radical scavenging assays: DPPH, nitric oxide radical scavenging, hydroxyl radical, reducing power, ferrous ion chelating ability and total antioxidant capacity. Results: Both the methanolic extract (at 150 and 300 mg/kg bw) and dehydroabietylamine (at 50 mg/kg bw) showed significant liver protection against CCl4 -induced liver damage that was comparable with the standard drug, silymarin (100 mg/kg bw), in reducing the elevated serum enzyme markers. The liver sections of the animals treated with dehydroabietylamine elicit a significant liver protection compared with the methanolic extract against CCl4 -induced liver damage. Further, both the methanolic extract and dehydroabietylamine exhibited a considerable and dose-dependent scavenging activity of DPPH, nitric oxide and hydroxyl radical. Similarly, in the reducing power assay, the results were very persuasive. In addition, the Fe2+ chelating activity and the total antioxidant assay established the antioxidant property of the methanolic extract and its isolated constituent. Among the two experimental samples, dehydroabietylamine proved to be more effective for the said parameters. Conclusion: The potent antioxidant and its correlative hepatoprotective activity of the methanolic extract and isolated constituent dehydroabietylamine is therefore attributed to its antioxidant and free radical scavenging activities.

Comparative Proteomic Analysis of Candida albicans and Candida glabrata

IntroductionCandida albicans and Candida glabrata are the two most common opportunistic pathogens which are part of the normal flora in humans. Clinical diagnosis of infection by these organisms is still largely based on culturing of these organisms. In order to identify species-specific protein expression patterns, we carried out a comparative proteomic analysis of C. albicans and C. glabrata.MethodsWe used “isobaric tag for relative and absolute quantitation” (iTRAQ) labeling of cell homogenates of C. albicans and C. glabrata followed by LC-MS/MS analysis using a quadrupole time-of-flight mass spectrometer. The MS/MS data was searched against a protein database comprised of known and predicted proteins reported from these two organisms. Subsequently, we carried out a bioinformatics analysis to group orthologous proteins across C. albicans and C. glabrata and calculated protein abundance changes between the two species.Results and ConclusionsWe identified 500 proteins from these organisms, the large majority of which corresponded to predicted transcripts. A number of proteins were observed to be significantly differentially expressed between the two species including enolase (Eno1), fructose-bisphosphate aldolase (Fba1), CCT ring complex subunit (Cct2), pyruvate kinase (Cdc19), and pyruvate carboxylase (Pyc2). This study illustrates a strategy for investigating protein expression patterns across closely related organisms by combining orthology information with quantitative proteomics.