Tropic Strains Research Articles

HIV and gp120-induced lipid droplets loss in hepatic stellate cells contribute to profibrotic profile

Liver fibrosis is the excessive accumulation of extracellular matrix proteins, primarily collagen, in response to liver injury caused by chronic liver diseases. HIV infection accelerates the progression of liver fibrosis in patients co-infected with HCV or HBV compared to those who are only mono-infected. The early event in the progression of liver fibrosis involves the activation of hepatic stellate cells (HSCs), which entails the loss of lipid droplets (LD) to fuel the production of extracellular matrix components crucial for liver tissue healing. Thus, we are examining the mechanism by which HIV stimulates the progression of liver fibrosis. HIV-R5 tropic infection was unable to induce the expression of TGF-β, collagen deposition, α-smooth muscle actin (α-SMA), and cellular proliferation. However, this infection induced the secretion of the profibrogenic cytokine IL-6 and the loss of LD. This process involved the participation of peroxisome proliferator-activated receptor (PPAR)-α and an increase in lysosomal acid lipase (LAL), along with the involvement of Microtubule-associated protein 1 A/1B-light chain 3 (LC3), strongly suggesting that LD loss could occur through acid lipolysis. These phenomena were mimicked by the gp120 protein from the R5 tropic strain of HIV. Preincubation of HSCs with the CCR5 receptor antagonist, TAK-779, blocked gp120 activity. Additionally, experiments performed with pseudotyped-HIV revealed that HIV replication could also contribute to LD loss. These results demonstrate that the cross-talk between HSCs and HIV involves a series of interactions that help explain some of the mechanisms involved in the exacerbation of liver damage observed in co-infected individuals.

Effectiveness of Rhizobium tropici sp. Strain UD5 Peat Biofertilizer Inoculant on Growth, Yield, and Nitrogen Concentration of Common Bean

Common bean (Phaseolus vulgaris L.) ranks among the most produced and consumed legume crops and contains essential macro- and micronutrients. Grain yield of the food crop is markedly decreased by poor management, especially a lack of additional essential nutrient elements through the application of fertilizers. In addition to the application of fertilizers, scholarly research and crop farmers have shown that the use of biofertilizer inoculants improves the yield of legume crops. The objective of this research study was to assess the effectiveness of peat-based Rhizobium tropici sp. UD5 on the growth, yield, and nitrogen concentration of common bean. The peat inoculant contained 6.5 × 109 viable cells/g. The experiment was conducted in two climatic zones, as described by the Koppen–Gieger climatic classification system. Treatments involved the peat-based inoculant Rhizobium tropici (T0 = 0 g without inoculation, T1 = 250 g of peat inoculant of strain UD5 for 50 kg seeds, T2 = 500 g of inoculant of strain UD5, and T3 = 200 g of comparative peat inoculant). The results indicated that common-bean-inoculated formulation of R. tropici sp. strain UD5 increased the following parameters compared to the controls: plant height (T1 = 18.22%, T2 = 20.41%, and T3 = 19.93% for bioclimatic zone 1; T1 = 16.78%, T2 = 20.71%, and T3 = 19.93% for bioclimatic zone 2), root length (T1 = 13.26%, T2 = 21.28%, and T3 = 19.38% for zone 1; T1 = 15.06%, T2 = 23.70%, and T3 = 19.20% for zone 2), number of nodules (T1 = 1162.57%, T2 = 1166.36%, and T3 = 1180.30% for zone 1; T1 = 1575%, T2 = 1616.5%, and T3 = 1608.25% for zone 2), size of nodules (T1 = 224.07%, T2 = 224.07%, and T3 = 208.33% for zone 1; T1 = 166.4%, T2 = 180%, and T3 = 140% for zone 2), and yield (T1 = 40.49%, T2 = 47.10%, and T3 = 45.45% for zone 1; T1 = 62.16%, T2 = 54.05%, and T3 = 58.55% for zone 2). R. tropici sp. UD5 peat inoculant formulation also increased the nitrogen concentration in leaves compared to the control (T1 = 3.75%, T2 = 1.12%, and T3 = 8.72%) in both bioclimatic zones. The findings of this study provide significant information on the positive effect of R. tropic UD5 strain peat inoculant application in the improvement of plant growth, development, and yield through the formation of nodules.

Prevalence of R5 and X4-Tropic strains in HIV-1 Infected bangladeshi population

PurposeHIV uses CD4 as main receptor to infect a cell. Also, it uses coreceptor (CCR5 or CXCR4) as a surrogate marker. In Bangladesh, nearly 50% of the identified strains are subtype C. In this study, we have examined viral genotypic co-receptor tropism in Bangladesh People Living with HIV (PLHIV). MethodsWe identified a co-receptor on V3 sequences of the HIV env gene. The online Geno2pheno tools was used. The threshold limit of a 10% false-positive rate was used. Samples from HIV-infected individuals aged 5–50 years were taken from which we obtained a good quality of 55 sequences. The viral tropism frequency in different circulating Bangladeshi HIV subtypes was analyzed using SPSS. ResultsAbove two third of the samples, (61.8%; 34 of 55) were HIV-1 subtype C. We identified 83.6% (46 of 55) of the samples were R5tropic, 16.4% (9 of 55) as X4 tropic, HIV-1 strains. The R5 tropic strains among key population infected with different HIV-1 subtype in the Bangladeshi population is common. ConclusionsThis finding can help with suitable drug selection in reverse-transcriptase (RT) or protease (PR) drug-resistance strains.

Strain-specific alterations in gut microbiome and host immune responses elicited by tolerogenic Bifidobacterium pseudolongum

The beneficial effects attributed to Bifidobacterium are largely attributed to their immunomodulatory capabilities, which are likely to be species- and even strain-specific. However, their strain-specificity in direct and indirect immune modulation remain largely uncharacterized. We have shown that B. pseudolongum UMB-MBP-01, a murine isolate strain, is capable of suppressing inflammation and reducing fibrosis in vivo. To ascertain the mechanism driving this activity and to determine if it is specific to UMB-MBP-01, we compared it to a porcine tropic strain B. pseudolongum ATCC25526 using a combination of cell culture and in vivo experimentation and comparative genomics approaches. Despite many shared features, we demonstrate that these two strains possess distinct genetic repertoires in carbohydrate assimilation, differential activation signatures and cytokine responses signatures in innate immune cells, and differential effects on lymph node morphology with unique local and systemic leukocyte distribution. Importantly, the administration of each B. pseudolongum strain resulted in major divergence in the structure, composition, and function of gut microbiota. This was accompanied by markedly different changes in intestinal transcriptional activities, suggesting strain-specific modulation of the endogenous gut microbiota as a key to immune modulatory host responses. Our study demonstrated a single probiotic strain can influence local, regional, and systemic immunity through both innate and adaptive pathways in a strain-specific manner. It highlights the importance to investigate both the endogenous gut microbiome and the intestinal responses in response to probiotic supplementation, which underpins the mechanisms through which the probiotic strains drive the strain-specific effect to impact health outcomes.

CRISPR-Cas9-mediated gene disruption of HIV-1 co-receptors confers broad resistance to infection in human T cells and humanized mice

In this preclinical study, we evaluated the efficacy and feasibility of creating broad human immunodeficiency virus (HIV) resistance by simultaneously disrupting the human CCR5 and CXCR4 genes, which encode cellular co-receptors required for HIV-1 infection. Using a clinically scalable system for transient ex vivo delivery of Cas9/guide RNA (gRNA) ribonucleoprotein (RNP) complexes, we demonstrated that CRISPR-mediated disruption of CCR5 and CXCR4 in T lymphocyte cells significantly reduced surface expression of the co-receptors, thereby establishing resistance to HIV-1 infection by CCR5 (R5)-tropic, CXCR4 (X4)-tropic, and dual (R5/X4)-tropic strains. Similarly, disruption of CCR5 alleles in human CD34+ hematopoietic stem and progenitor cells (HSPCs) successfully led to the differentiation of HIV-resistant macrophages. In a humanized mouse model under HIV-1 challenge, CXCR4-disrupted CD4+ T cells were enriched in the peripheral blood and spleen, indicating survival advantage because of resistance to viral infection. However, in human CD4+ T cells with both CCR5 and CXCR4 disruption, we observed poor engraftment in bone marrow, although significant changes were not observed in the lung, spleen, or peripheral blood. This study establishes a clinically scalable strategy for the dual knockout of HIV-1 co-receptors as a therapeutic strategy, while also raising caution of disrupting CXCR4, which may abate engraftment of CD4+ T cells in bone marrow.

A trimeric capable gB CMV vaccine provides limited protection against a highly cell associated and epithelial tropic strain of cytomegalovirus in guinea pigs.

Multiple strains of human cytomegalovirus (HCMV) can cause congenital cytomegalovirus (cCMV) by primary or secondary infection. The viral gB glycoprotein is a leading vaccine candidate, essential for infection of all cell-types, and immunodominant antibody target. Guinea pig cytomegalovirus (GPCMV) is the only small animal model for cCMV. Various gB vaccines have shown efficacy but studies have utilized truncated gB and protection against prototype strain 22122 with preferential tropism to fibroblasts despite encoding a gH-based pentamer complex for non-fibroblast infection. A highly cell-associated novel strain of GPCMV (TAMYC) with 99 % identity in gB sequence to 22122 exhibited preferred tropism to epithelial cells. An adenovirus vaccine encoding full-length gB (AdgB) was highly immunogenic and partially protected against 22122 strain challenge in vaccinated animals but not when challenged with TAMYC strain. GPCMV studies with AdgB vaccine sera on numerous cell-types demonstrated impaired neutralization (NA50) compared to fibroblasts. GPCMV-convalescent sera including pentamer complex antibodies increased virus neutralization on non-fibroblasts and anti-gB depletion from GPCMV-convalescent sera had minimal impact on epithelial cell neutralization. GPCMV(PC+) 22122-convalescent animals challenged with TAMYC exhibited higher protection compared to AdgB vaccine. Overall, results suggest that antibody response to both gB and PC are important components of a GPCMV vaccine.

New Insights Into the Physiopathology of COVID-19: SARS-CoV-2-Associated Gastrointestinal Illness.

Although SARS-CoV-2 is considered a lung-tropic virus that infects the respiratory tract through binding to the ACE2 cell-surface molecules present on alveolar lungs epithelial cells, gastrointestinal symptoms have been frequently reported in COVID-19 patients. What can be considered an apparent paradox is that these symptoms (e.g., diarrhea), sometimes precede the development of respiratory tract illness as if the breathing apparatus was not its first target during viral dissemination. Recently, evidence was reported that the gut is an active site of replication for SARS-CoV-2. This replication mainly occurs in mature enterocytes expressing the ACE2 viral receptor and TMPRSS4 protease. In this review we question how SARS-CoV-2 can cause intestinal disturbances, whether there are pneumocyte-tropic, enterocyte-tropic and/or dual tropic strains of SARS-CoV-2. We examine two major models: first, that of a virus directly causing damage locally (e.g., by inducing apoptosis of infected enterocytes); secondly, that of indirect effect of the virus (e.g., by inducing changes in the composition of the gut microbiota followed by the induction of an inflammatory process), and suggest that both situations probably occur simultaneously in COVID-19 patients. We eventually discuss the consequences of the virus replication in brush border of intestine on long-distance damages affecting other tissues/organs, particularly lungs.

Generation of Liposomes to Study the Effect of Mycobacterium Tuberculosis Lipids on HIV-1 cis- and trans-Infections.

Tuberculosis (TB) is the leading cause of death among HIV-1-infected individuals and Mycobacterium tuberculosis (Mtb) co-infection is an early precipitate to AIDS. We aimed to determine whether Mtb strains differentially modulate cellular susceptibility to HIV-1 infection (cis- and trans-infection), via surface receptor interaction by their cell envelope lipids. Total lipids from pathogenic (lineage 4 Mtb H37Rv, CDC1551 and lineage 2 Mtb HN878, EU127) and non-pathogenic (Mycobacterium bovis BCG and Mycobacterium smegmatis) Mycobacterium strains were integrated into liposomes mimicking the lipid distribution and antigen accessibility of the mycobacterial cell wall. The resulting liposomes were tested for modulating in vitro HIV-1 cis- and trans-infection of TZM-bl cells using single-cycle infectious virus particles. Mtb glycolipids did not affect HIV-1 direct infection however, trans-infection of both R5 and X4 tropic HIV-1 strains were impaired in the presence of glycolipids from M. bovis, Mtb H37Rv and Mtb EU127 strains when using Raji-DC-SIGN cells or immature and mature dendritic cells (DCs) to capture virus. SL1, PDIM and TDM lipids were identified to be involved in DC-SIGN recognition and impairment of HIV-1 trans-infection. These findings indicate that variant strains of Mtb have differential effect on HIV-1 trans-infection with the potential to influence HIV-1 disease course in co-infected individuals.

Portable and sensitive Ag nanorods based SERS platform for rapid HIV-1 detection and tropism determination

In this study, surface-enhanced Raman scattering (SERS) based field-deployable platform has been explored for early detection and distinction of the human immunodeficiency virus (HIV-1). A highly optimized silver nanorods array, fabricated using glancing angle deposition technique was used as SERS substrate. Distinct signature peaks for varying concentrations (102 to 106 copies/mL) were identified in five different HIV-1 subtypes (A, B, C, D, and CRF02_AG). Binding of viruses directly with Ag nanorods without using antibodies or intermediate reagents is shown. The purified viruses were spiked in water and healthy plasma to capture pure HIV-1 peaks. Distinct peaks were also captured for the X4 and R5 tropic strains suggesting tropism based detection. The above data was further confirmed and analyzed statistically using a multivariate tool. Thus, the present study indicates the ability of the SERS platform to detect and differentiate the HIV-1 virus implying its further validation using clinical specimens and isolates.

HIV glycoprotein gp120 enhances mesenchymal stem cell migration by upregulating CXCR4 expression

BackgroundHIV infection and/or the direct pathogenic effects of circulating HIV proteins impairs the physiological function of mesenchymal stem cells (MSCs), and contribute to the pathogenesis of age-related clinical comorbidities in people living with HIV. The SDF-1/CXCR4 pathway is vital for modulating MSC proliferation, migration and differentiation. HIV glycoprotein gp120 inhibits SDF-1 induced chemotaxis by downregulating the expression and function of CXCR4 in monocytes, B and T cells. The influence of gp120 on CXCR4 expression and migration in MSCs is unknown. MethodsWe investigated CXCR4 expression and SDF-1/CXCR4-mediated MSC migration in response to gp120, and its effect on downstream signaling pathways: focal adhesion kinase (FAK)/Paxillin and extracellular signal-regulated kinase (ERK). ResultsGp120 upregulated MSC CXCR4 expression. This potentiated the effects of SDF-1 in inducing chemotaxis; FAK/Paxillin and ERK pathways were over-activated, thereby facilitating actin stress fiber reorganization. CXCR4 blockage or depletion abrogated the observed effects. ConclusionGp120 from both T- and M- tropic HIV strains upregulated CXCR4 expression in MSCs, resulting in enhanced MSC chemotaxis in response to SDF-1. General significanceHIV infection and its proteins are known to disrupt physiological differentiation of MSC; increased gp120-driven migration amplifies the total MSC population destined for ineffective and inappropriate differentiation, thus contributing to the pathogenesis of HIV-related comorbidities. Additionally, given that MSCs are permissive to HIV infection, initial cellular priming by gp120 results in increased expression of CXCR4 and could lead to co-receptor switching and cell tropism changes in chronic HIV infection and may have implications against CCR5-knockout based HIV cure strategies.

Combustion characteristics and kinetics of five tropic oilgal strains using thermogravimetric analysis

In order to utilize the microalgal biomass sufficiently, thermogravimetry experimentation analyses of five microalgal strains (Chlorella sorokiniana C74 (C. sorokiniana C74), Desmodesmus sp. WC08, Chlorella sorokiniana XS04 (C. sorokiniana XS04), Scenedesmus ecornis G2 (S. ecornis G2) and Dictyosphaerium sp. 1A10) were performed by using TG–DTG–DSC (thermogravimetric–differential thermogravimetric–differential scanning calorimetry) thermal analysis technology. The combustion indexes, parameters and synthetic combustion characteristics were investigated. Meanwhile, the combustion kinetics parameters were identified with heating rates from 5 to 40 °C min−1 and conversion fractions from 0.1 to 0.9. The results showed that the burning TG–DTG curves of all five microalgal strains were different and the exothermic regions of five microalgal strains in DSC curves were different as well. The variation trends of apparent activation energy of Dictyosphaerium sp. 1A10, C. sorokiniana C74, C. sorokiniana XS04 and S. ecornis G2 differed from Desmodesmus sp. WC08. The average apparent activation energy of Desmodesmus sp. WC08 was highest followed by C. sorokiniana C74, Dictyosphaerium sp. 1A10, C. sorokiniana XS04 and S. ecornis G2.

Structural diversity of Burkholderia pseudomallei lipopolysaccharides affects innate immune signaling.

Burkholderia pseudomallei (Bp) causes the disease melioidosis. The main cause of mortality in this disease is septic shock triggered by the host responding to lipopolysaccharide (LPS) components of the Gram-negative outer membrane. Bp LPS is thought to be a weak inducer of the host immune system. LPS from several strains of Bp were purified and their ability to induce the inflammatory mediators TNF-α and iNOS in murine macrophages at low concentrations was investigated. Innate and adaptive immunity qPCR arrays were used to profile expression patterns of 84 gene targets in response to the different LPS types. Additional qPCR validation confirmed large differences in macrophage response. LPS from a high-virulence serotype B strain 576a and a virulent rough central nervous system tropic strain MSHR435 greatly induced the innate immune response indicating that the immunopathogenesis of these strains is different than in infections with strains similar to the prototype strain 1026b. The accumulation of autophagic vesicles was also increased in macrophages challenged with highly immunogenic Bp LPS. Gene induction and concomitant cytokine secretion profiles of human PBMCs in response to the various LPS were also investigated. MALDI-TOF/TOF was used to probe the lipid A portions of the LPS, indicating substantial structural differences that likely play a role in host response to LPS. These findings add to the evolving knowledge of host-response to bacterial LPS, which can be used to better understand septic shock in melioidosis patients and in the rational design of vaccines.

The Role of Neurotropism in HIV‐1 gp120 Induced Oxidative Stress and Neurodegeneration

Human immunodeficiency virus 1 (HIV‐1) infection is linked to late onset neurological and cognitive dysfunctions, termed HIV associated neurocognitive disorders (HAND), despite the use of antiretroviral therapies. Each stage of the HIV‐1 life cycle (binding, fusion, and subsequent budding) critically depends on host‐cell lipid raft domains. Entry of HIV‐1 into neurons requires binding of the viral surface glycoprotein gp120 to CD4 receptors in lipid raft domains and subsequent conformational changes facilitate recruitment of the chemokine co‐receptors CCR5 or CXCR4. The preferential binding of gp120 to co‐receptors determines viral tropism, with R5 tropic strains binding CCR5, X4 tropic strains binding CXCR4, and dual tropic R5/X4 strains binding both receptors. Notably, X4 and dual‐tropic strains of HIV‐1 gp120 emerge later in infection and correspond with onset of neurological symptoms reminiscent of Alzheimer's disease (AD). Interestingly, binding of both dual‐tropic gp120MN and soluble, oligomeric amyloid β (Aβ) induces raft coalescence into membrane macrodomains. Exposure of human SH‐SY5Y neuroblastoma cells to 250, 500, and 750pg gp120MN over time (2.5, 5, and 7.5 hrs.) led to an increase in raft coalescence. Treatment with 750pg gp120MN for 2.5 hours lead to a significant increase in raft area/intensity ratio, (H=432.2, 5 df, n=9, p<0.0001), with significant increases (*p£0.05) detected for all doses at 5 and 7.5 hours. A signaling pathway common to gp120, Aβ, and several cytokines has been implicated in the production of reactive oxygen species (ROS) by neuronal NADPH oxidase 2 (NOX2) and the generation of rod‐like actin inclusions in primary hippocampal neurons. Hippocampal neurons exposed to1 ng/ml gp120MN provoked a rapid 22–25% increase in ROS production and a significant increase in the percentage of neurons with rods in a dose/time dependent manner (15.3±1.9 vs. 39.5±9.6 % neurons w/rods, control and 750pM gp120 respectively. p<0.05, n=3, 16hr incubation). Generation of rods was abolished by inhibiting NOX2, suggesting a causative role for NOX2‐mediated ROS activation in the formation of actin rods.To further explore the role of HIV‐1 neurotropism in neurodegeneration, we characterized the involvement of CCR5 and CXCR4 co‐receptors using R5 and X4 tropic gp120 (gp120CM and gp120LAV, respectively). Previously it was suggested that the tropic switch from R5 to X4 gp120 may trigger early manifestations of HAND through a more potent activation of the NOX2 mediated generation of ROS and actin rods. Preliminary results suggest that gp120LAV (X4‐tropic) stimulates increases in lipid raft coalescence as well as increased ROS generation in SH‐SY5Y neuroblastoma cells, and the generation of rod‐like actin inclusions in E18 rat hippocampal neurons.Support or Funding InformationSupported in part by NIH grants AG044812, AG049668, Camille & Henry Dreyfus Sr. Scientist Mentor Award, and CSU Core Infrastructure Grant Microscope Imaging (JRB), and P20GM103395 and the Alzheimer's Resources of Alaska (TBK). Research reported in this publication was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Numbers UL1GM118991, TL4GM118992, or RL5GM118990. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health (LKS).

M48U1 and Tenofovir combination synergistically inhibits HIV infection in activated PBMCs and human cervicovaginal histocultures

Microbicides are considered a promising strategy for preventing human immunodeficiency virus (HIV-1) transmission and disease. In this report, we first analyzed the antiviral activity of the miniCD4 M48U1 peptide formulated in hydroxyethylcellulose (HEC) hydrogel in activated peripheral blood mononuclear cells (PBMCs) infected with R5- and X4–tropic HIV-1 strains. The results demonstrate that M48U1 prevented infection by several HIV-1 strains including laboratory strains, and HIV-1 subtype B and C strains isolated from the activated PBMCs of patients. M48U1 also inhibited infection by two HIV-1 transmitted/founder infectious molecular clones (pREJO.c/2864 and pTHRO.c/2626). In addition, M48U1 was administered in association with tenofovir, and these two antiretroviral drugs synergistically inhibited HIV-1 infection. In the next series of experiments, we tested M48U1 alone or in combination with tenofovir in HEC hydrogel with an organ-like structure mimicking human cervicovaginal tissue. We demonstrated a strong antiviral effect in absence of significant tissue toxicity. Together, these results indicate that co-treatment with M48U1 plus tenofovir is an effective antiviral strategy that may be used as a new topical microbicide to prevent HIV-1 transmission.

HIV Infects Bronchial Epithelium and Suppresses Components of the Mucociliary Clearance Apparatus.

Recurrent lung infections and pneumonia are emerging as significant comorbidities in the HIV-infected population in the era of combination antiretroviral therapy (cART). HIV infection has been reported to suppress nasal mucociliary clearance (MCC). Since the primary components driving nasal MCC and bronchial MCC are identical, it is possible that bronchial MCC is affected as well. Effective MCC requires optimal ciliary beating which depends on the maintenance of the airway surface liquid (ASL), a function of cystic fibrosis transmembrane conductance regulator (CFTR) activity and the integrity of the signaling mechanism that regulates ciliary beating and fluid secretion. Impairment of either component of the MCC apparatus can compromise its efficacy and promote microbial colonization. We demonstrate that primary bronchial epithelium expresses HIV receptor CD4 and co-receptors CCR5 and CXCR4 and can be infected by both R5 and X4 tropic strains of HIV. We show that HIV Tat suppresses CFTR biogenesis and function in primary bronchial epithelial cells by a pathway involving TGF-β signaling. HIV infection also interferes with bronchial epithelial cell differentiation and suppresses ciliogenesis. These findings suggest that HIV infection suppresses tracheobronchial mucociliary clearance and this may predispose HIV-infected patients to recurrent lung infections, pneumonia and chronic bronchitis.

Cell-Delivered Entry Inhibitors for HIV-1: CCR5 Downregulation and Blocking Virus/Membrane Fusion in Defending the Host Cell Population.

HIV-1 infection requires the presence of the CD4 receptor on the target cell surface and a coreceptor, predominantly CC-chemokine receptor 5 (CCR5). It has been shown that individuals who are homozygous for a defective CCR5 gene are protected from HIV-1 infection. A novel self-inactivating lentiviral vector LVsh5/C46 (Cal-1) has been engineered to block HIV-1 infection with two viral entry inhibitors, conferring resistance to HIV-1 infection from both CCR5 and CXCR4 tropic strains. Cal-1 encodes a short hairpin RNA (sh5) to downregulate CCR5 and C46, an HIV-1 fusion inhibitor. Gene therapy by Cal-1 is aimed at transducing CD4+ T cells and CD34+ hematopoietic stem/progenitor cells in an autologous transplant setting. Pre-clinical safety and efficacy studies in vitro and in vivo (humanized mouse model and nonhuman primates) have shown that Cal-1 is safe with no indication of any toxicity risk and acts to decrease viral load and increase CD4 counts. Two clinical trials are underway using Cal-1: a phase I/II study to assess safety and feasibility in an adult HIV-1-positive population not on antiretroviral therapy (ART); and a second Fred Hutchinson Investigator Initiated phase I study to assess safety and feasibility in adults with HIV-1-associated non-Hodgkin or Hodgkin lymphoma.

Cloning of the Human C5a Anaphylatoxin Receptor, and More.

Cloning of the Human C5a Anaphylatoxin Receptor, and More.

Cells Harvesting of Tropic Ocean Oleaginous Microalga Strain Desmodesmus Sp. WC08

For biomass recovery of tropic ocean oleaginous microalgae strain Desmodesmus sp. WC08, eight flocculation methods (pH adjustment, Al2 (SO4)3, polyacrylamide, AlCl3, Ca (OH) 2, FeCl3, alum and chitosan) were evaluated and optimized. The results indicated that ferric chloride, aluminum sulfate, aluminum chloride and chitosan exhibited high flocculation ability and their flocculation efficiency were all beyond 94% at the optimal dosage (0.15, 0.4 and 0.03 gL-1, respectively). Chitosan displayed the most tremendous potential for biomass recovery from culture broth based on its feasibility and safety. Acetic acid and hydrous chloride, used to dissolving chitosan, had no significant difference in the flocculation efficiency. And when the pH of culture broth was set 5 or 6, the flocculation efficiency of chitosan was higher and the required flocculation time was less. More dose chitosan was needed to harvest the biomass following the cell growth stage. Overall, the optimal flocculation reagent for harvesting biomass of Desmodesmus sp. WC08 is chitosan, and its optimal flocculation conditions are: just when the pH of the culture broth was set to 6 and the dosage of chitosan was 0.03 g/L at the end of microalgae cultivation, more than 110g of algal biomass can be recovered just by per 1 g of chitosan. Meanwhile, there is little residual chitosan found in the final flocculation supernatant which can be reused to some extent.

Hematopoietic Stem Cell-Based Therapy for HIV Disease: A Role for Regulatory T Cells

The goal of this review is to develop insight and understanding of the effect of deleting the chemokine receptor CCR5 in T cells, and its interplay with immune regulation of Human Immunodeficiency Virus type–1 (HIV-1), to enable a novel technology platform to cure HIV disease. A critical point is the use Hematopoietic Stem Cell (HSC) transplantation of the cells resistant to HIV such as CCR5Δ32 cells, which harbor deletion in the CCR5 promoter. Such mutations, which spontaneously occur in 4-15% of the European or US populations confer resistance to CCR5-tropic HIV-1 in homozygous individuals and could cure HIV-1 disease based on the outcome of bone marrow engraftment in HIV+ leukemic patients using a CCR5Δ32 homozygous donor (e.g. ‘Berlin Patient’). However, potential shift of HIV tropism to CXCR-4 tropic strains of HIV-1 is limiting after HSC transplantation with CCR5Δ32/Δ32 donor since it could lead to recurrence of viremia (e.g. ‘Essen patient’). In addition, patients receiving allogeneic bone marrow transplantation often suffer from Graft-Versus-Host Disease (GvHD), and for that reason HIV infection is not considered an indication, unless a hematologic malignancy warrants transplantation. To advance this field, it is, however, vital i) to search for novel determinants to HIV susceptibility using genome-wide analyses and ii) exploit mechanisms, which play a crucial role in amelioration of GvHD such as repression of conventional CD4+ T cells (Tcons) by naturally occurring regulatory CD4+CD25+ T cells (nTregs). Transfer of cyclic AMP (cAMP) from nTregs to Tcons underpins function of potent transcriptional repressor termed inducible cAMP early repressor (ICER) leading to suppression of interleukin-2 (IL-2) synthesis in Tcons. Further understanding of the mechanisms of immunological self-tolerance will also provide insights into how strong immune responses such as graft rejection could be restrained and engraftment of HIV resistant cells in HIV+ leukemic patients could be augmented.

Targeting chemokine receptor CXCR4 for treatment of HIV-1 infection, tumor progression, and metastasis.

The chemokine receptor CXCR4 is required for the entry of human immunodeficiency virus type 1 (HIV-1) into target cells and for the development and dissemination of various types of cancers, including gastrointestinal, cutaneous, head and neck, pulmonary, gynecological, genitourinary, neurological, and hematological malignancies. The T-cell (T)-tropic HIV-1 strains use CXCR4 as the entry coreceptor; consequently, multiple CXCR4 antagonistic inhibitors have been developed for the treatment of acquired immune deficiency syndrome (AIDS). However, other potential applications of CXCR4 antagonists have become apparent since its discovery in 1996. In fact, increasing evidence demonstrates that epithelial and hematopoietic tumor cells exploit the interaction between CXCR4 and its natural ligand, stromal cellderived factor (SDF)-1α, which normally regulates leukocyte migration. The CXCR4 and/or SDF-1α expression patterns in tumor cells also determine the sites of metastatic spread. In addition, the activation of CXCR4 by SDF-1α promotes invasion and proliferation of tumor cells, enhances tumor-associated neoangiogenesis, and assists in the degradation of the extracellular matrix and basement membrane. As such, the evaluation of CXCR4 and/or SDF-1α expression levels has a significant prognostic value in various types of malignancies. Several therapeutic challenges remain to be overcome before the use of CXCR4 inhibitors can be translated into clinical practice, but promising preclinical data demonstrate that CXCR4 antagonists can mobilize tumor cells from their protective microenvironments, interfere with their metastatic and tumorigenic potentials, and/or make tumor cells more susceptible to chemotherapy.