Adipose Tissue Is a Neglected Viral Reservoir and an Inflammatory Site during Chronic HIV and SIV Infection

Two of the crucial aspects of human immunodeficiency virus (HIV) infection are (i) viral persistence in reservoirs (precluding viral eradication) and (ii) chronic inflammation (directly associated with all-cause morbidities in antiretroviral therapy (ART)-controlled HIV-infected patients). The objective of the present study was to assess the potential involvement of adipose tissue in these two aspects. Adipose tissue is composed of adipocytes and the stromal vascular fraction (SVF); the latter comprises immune cells such as CD4⁺ T cells and macrophages (both of which are important target cells for HIV). The inflammatory potential of adipose tissue has been extensively described in the context of obesity. During HIV infection, the inflammatory profile of adipose tissue has been revealed by the occurrence of lipodystrophies (primarily related to ART). Data on the impact of HIV on the SVF (especially in individuals not receiving ART) are scarce. We first analyzed the impact of simian immunodeficiency virus (SIV) infection on abdominal subcutaneous and visceral adipose tissues in SIVmac251 infected macaques and found that both adipocytes and adipose tissue immune cells were affected. The adipocyte density was elevated, and adipose tissue immune cells presented enhanced immune activation and/or inflammatory profiles. We detected cell-associated SIV DNA and RNA in the SVF and in sorted CD4⁺ T cells and macrophages from adipose tissue. We demonstrated that SVF cells (including CD4⁺ T cells) are infected in ART-controlled HIV-infected patients. Importantly, the production of HIV RNA was detected by in situ hybridization, and after the in vitro reactivation of sorted CD4⁺ T cells from adipose tissue. We thus identified adipose tissue as a crucial cofactor in both viral persistence and chronic immune activation/inflammation during HIV infection. These observations open up new therapeutic strategies for limiting the size of the viral reservoir and decreasing low-grade chronic inflammation via the modulation of adipose tissue-related pathways.     

Ultrafiltration system for cyclodextrin production in repetitive batches by CGTase from <Emphasis Type="Italic">Bacillus firmus</Emphasis> strain 37

This study aimed to improve the yield of cyclodextrins (CDs) production in repetitive batches. An innovative ultrafiltration system was used to remove the inhibitory products that accumulated in the medium and to recover the enzyme. The assays were performed with the CGTase from Bacillus firmus strain 37 in purified, semi-purified, and crude extract forms. Maltodextrin (10 % w/v) and corn starch (5 % w/v) were used as substrates. After eight repetitive 24-h batches, the yield of β-CD obtained with the purified enzyme and the corn starch substrate was 0.54 mmol/L/h, which was 36 % greater than that observed with the 10 % maltodextrin substrate. The crude CGTase extract with the corn starch substrate showed a productivity of 0.38 mmol/L/h, which was 29 % lower than using the purified enzyme and the corn starch substrate but 7 % higher than using the purified enzyme and the maltodextrin substrate. The crude extract, assayed with the corn starch substrate in the presence of 10 % ethanol reached 0.43 mmol/L/h productivity, which was 12 % higher compared to the assay without ethanol. The semi-purified enzyme was assayed with the corn starch substrate in the presence of 10 % ethanol for eight batches lasting 12 h and an excellent selectivity for the β-CD was obtained, reaching a mean percentage of 96.0 %. Therefore, this ultrafiltration system enabled several batches of CD production, with efficient removal of products inhibitory to the CGTase and recovery of the enzyme. The possibility of industrial application of this system is promising.     

Gene duplication within the Green Lineage: the case of TEL genes

Recent years have witnessed a breathtaking increase in the availability of genome sequence data, providing evidence of the highly duplicate nature of eukaryotic genomes. Plants are exceptional among eukaryotic organisms in that duplicate loci compose a large fraction of their genomes, partly because of the frequent occurrence of polyploidy (or whole-genome duplication) events. Tandem gene duplication and transposition have also contributed to the large number of duplicated genes in plant genomes. Evolutionary analyses allowed the dynamics of duplicate gene evolution to be studied and several models were proposed. It seems that, over time, many duplicated genes were lost and some of those that were retained gained new functions and/or expression patterns (neofunctionalization) or subdivided their functions and/or expression patterns between them (subfunctionalization). Recent studies have provided examples of genes that originated by duplication with successive diversification within plants. In this review, we focused on the TEL (TERMINAL EAR1-like) genes to illustrate such mechanisms. Emerged from the mei2 gene family, these TEL genes are likely to be land plant-specific. Phylogenetic analyses revealed one or two TEL copies per diploid genome. TEL gene degeneration and loss in several Angiosperm species such as in poplar and maize seem to have occurred. In Arabidopsis thaliana, whose genome experienced at least three polyploidy events followed by massive gene loss and genomic reorganization, two TEL genes were retained and two new shorter TEL-like (MCT) genes emerged. Molecular and expression analyses suggest for these genes sub- and neofunctionalization events, but confirmation will come from their functional characterization.     

Arthritogenic self-reactive CD4+ T cells acquire an FR4hiCD73hi anergic state in the presence of Foxp3+ regulatory T cells

Rheumatoid arthritis develops in association with a defect in peripheral CD4(+) T cell homeostasis. T cell lymphopenia has also been shown to be a barrier to CD4(+) T cell clonal anergy induction. We therefore explored the relationship between clonal anergy induction and the avoidance of autoimmune arthritis by tracking the fate of glucose-6-phosphate isomerase (GPI)-reactive CD4(+) T cells in the setting of selective T cell lymphopenia. CD4(+) T cell recognition of self-GPI peptide/MHC class II complexes in normal murine hosts did not lead to arthritis and instead caused those T cells to develop a Folate receptor 4(hi)CD73(hi) anergic phenotype. In contrast, hosts selectively depleted of polyclonal Foxp3(+)CD4(+) regulatory T cells could not make GPI-specific CD4(+) T cells anergic and failed to control arthritis. This suggests that autoimmune arthritis develops in the setting of lymphopenia when Foxp3(+)CD4(+) regulatory T cells are insufficient to functionally inactivate all autoreactive CD4(+) T cells that encounter self-Ag.     

Immunological disruption of antiangiogenic signals by recruited allospecific T cells leads to corneal allograft rejection

Corneal transplantation is the most common solid organ transplantation. The immunologically privileged nature of the cornea results in high success rates. However, T cell-mediated rejection is the most common cause of corneal graft failure. Using antiangiogenesis treatment to prevent corneal neovascularization, which revokes immune privilege, prevents corneal allograft rejection. Endostatin is an antiangiogenic factor that maintains corneal avascularity. In this study, we directly test the role of antiangiogenic and immunological signals in corneal allograft survival, specifically the potential correlation of endostatin production and T cell recruitment. We report that 75% of the corneal allografts of BALB/c mice rejected after postoperative day (POD) 20, whereas all syngeneic grafts survived through POD60. This correlates with endogenous endostatin, which increased and remained high in syngeneic grafts but decreased after POD10 in allografts. Immunostaining demonstrated that early recruitment of allospecific T cells into allografts around POD10 correlated with decreased endostatin production. In Rag(-/-) mice, both allogeneic and syngeneic corneal grafts survived; endostatin remained high throughout. However, after T cell transfer, the allografts eventually rejected, and endostatin decreased. Furthermore, exogenous endostatin treatment delayed allograft rejection and promoted survival secondary to angiogenesis inhibition. Our results suggest that endostatin plays an important role in corneal allograft survival by inhibiting neovascularization and that early recruitment of allospecific T cells into the grafts promotes destruction of endostatin-producing cells, resulting in corneal neovascularization, massive infiltration of effector T cells, and ultimately graft rejection. Therefore, combined antiangiogenesis and immune suppression will be more effective in maintaining corneal allograft survival.     

Melanogenesis stimulation in B16-F10 melanoma cells induces cell cycle alterations, increased ROS levels and a differential expression of proteins as revealed by proteomic analysis

Considering that stimulation of melanogenesis may lead to alterations of cellular responses, besides melanin production, our main goal was to study the cellular effects of melanogenesis stimulation of B16-F10 melanoma cells. Our results show increased levels of the reactive oxygen species after 15 h of melanogenesis stimulation. Following 48 h of melanogenesis stimulation, proliferation was inhibited (by induction of cell cycle arrest in the G1 phase) and the expression levels of p21 mRNA were increased. In addition, melanogenesis stimulation did not induce cellular senescence. Proteomic analysis demonstrated the involvement of proteins from other pathways besides those related to the cell cycle, including protein disulfide isomerase A3, heat-shock protein 70, and fructose biphosphate aldolase A (all up-regulated), and lactate dehydrogenase (down-regulated). In RT-qPCR experiments, the levels of pyruvate kinase M2 mRNA dropped, whereas the levels of ATP synthase (beta-F1) mRNA increased. These data indicate that melanogenesis stimulation of B16-F10 cells leads to alterations in metabolism and cell cycle progression that may contribute to an induction of cell quiescence, which may provide a mechanism of resistance against cellular injury promoted by melanin synthesis.