T Cell Effector Responses in HIV-1 Cure Strategies

HIV-1 is a virus that affects over 35 million individuals around the world, and yet despite present treatments, there remains a need for a cure. A current cure tactic widely researched is the “shock and kill” strategy, where cART-treated HIV-positive individuals would be given latency reactivating agents (LRAs) to induce HIV-1 production from latently-infected CD4+ T cells, allowing for the CD8+ T cell response to eliminate the latent reservoir. Here, I examined the capabilities of the CD8+ T cell response from HIV-positive individuals to eliminate macrophages, another cell type infected by HIV-1, and reactivated latently-infected primary CD4+ T cells, both reactivated with PMA and ionomycin and with LRAs. Both CD4+ and CD8+ T cells from elite suppressors, HIV-positive individuals with viral loads of less than 50 copies per milliliter of blood, were capable of suppressing virus production from HIV-infected monocyte-derived macrophages, with the CD8+ T cells actually killing the infected cells. As to the latently-infected CD4+ T cells, CD8+ T cells from chronic progressors were not consistently capable of eliminating the infected cells upon reactivation, although those from two of four viremic controllers were when PMA and ionomycin were used for stimulation. Treatment with LRAs such as bryostatin and romidepsin both alone and in combination significantly inhibited the CD8+ T cell response to HIV-1, with the mechanism for bryostatin inhibition being an increase in cell death, downregulation of CD3, and upregulation of exhaustion markers. Despite that the elite suppressor CD8+ T cell response was capable of inhibiting HIV-1 infection of macrophages and that the response of some viremic controllers and chronic progressors can do so for latently-infected CD4+ T cells, there remains a need for some sort of immunologic boost for the average individual with HIV-1 infection. Worse, some LRAs and combinations of LRAs decrease the ability of the CD8+ T cell response to eliminate infected CD4+ T cells. Therefore, any given LRA or combination of LRAs should be examined for their effects upon the adaptive immune response prior to use in clinical investigations of HIV-1 cure strategies

CCR5AS lncRNA variation differentially regulates CCR5, influencing HIV disease outcome.

Multiple genome-wide studies have identified associations between outcome of human immunodeficiency virus (HIV) infection and polymorphisms in and around the gene encoding the HIV co-receptor CCR5, but the functional basis for the strongest of these associations, rs1015164A/G, is unknown. We found that rs1015164 marks variation in an activating transcription factor 1 binding site that controls expression of the antisense long noncoding RNA (lncRNA) CCR5AS. Knockdown or enhancement of CCR5AS expression resulted in a corresponding change in CCR5 expression on CD4+ T cells. CCR5AS interfered with interactions between the RNA-binding protein Raly and the CCR5 3' untranslated region, protecting CCR5 messenger RNA from Raly-mediated degradation. Reduction in CCR5 expression through inhibition of CCR5AS diminished infection of CD4+ T cells with CCR5-tropic HIV in vitro. These data represent a rare determination of the functional importance of a genome-wide disease association where expression of a lncRNA affects HIV infection and disease progression

Factors Associated With the Control of Viral Replication and Virologic Breakthrough in a Recently Infected HIV-1 Controller

HIV-1 controllers are patients who control HIV-1 viral replication without antiretroviral therapy. Control is achieved very early in the course of infection, but the mechanisms through which viral replication is restricted are not fully understood. We describe a patient who presented with acute HIV-1 infection and was found to have an HIV-1 RNA level of < 100 copies/mL. She did not have any known protective HLA alleles, but significant immune activation of CD8 + T cells and natural killer (NK) cells was present, and both cell types inhibited viral replication. Virus cultured from this patient replicated as well in vitro as virus isolated from her partner, a patient with AIDS who was the source of transmission. Virologic breakthrough occurred 9 months after her initial presentation and was associated with an increase in CD4 + T cell activation levels and a significant decrease in NK cell inhibitory capacity. Remarkably, CD8 + T cell inhibitory capacity was preserved and there were no new escape mutations in targeted Gag epitopes. These findings suggest that fully replication-competent virus can be controlled in acute HIV-1 infection in some patients without protective HLA alleles and that NK cell responses may contribute to this early control of viral replication

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Conversion Discriminative Analysis on Mild Cognitive Impairment Using Multiple Cortical Features from MR Images

Neuroimaging measurements derived from magnetic resonance imaging provide important information required for detecting changes related to the progression of mild cognitive impairment (MCI). Cortical features and changes play a crucial role in revealing unique anatomical patterns of brain regions, and further differentiate MCI patients from normal states. Four cortical features, namely, gray matter volume, cortical thickness, surface area, and mean curvature, were explored for discriminative analysis among three groups including the stable MCI (sMCI), the converted MCI (cMCI), and the normal control (NC) groups. In this study, 158 subjects (72 NC, 46 sMCI, and 40 cMCI) were selected from the Alzheimer's Disease Neuroimaging Initiative. A sparse-constrained regression model based on the l2-1-norm was introduced to reduce the feature dimensionality and retrieve essential features for the discrimination of the three groups by using a support vector machine (SVM). An optimized strategy of feature addition based on the weight of each feature was adopted for the SVM classifier in order to achieve the best classification performance. The baseline cortical features combined with the longitudinal measurements for 2 years of follow-up data yielded prominent classification results. In particular, the cortical thickness produced a classification with 98.84% accuracy, 97.5% sensitivity, and 100% specificity for the sMCI–cMCI comparison; 92.37% accuracy, 84.78% sensitivity, and 97.22% specificity for the cMCI–NC comparison; and 93.75% accuracy, 92.5% sensitivity, and 94.44% specificity for the sMCI–NC comparison. The best performances obtained by the SVM classifier using the essential features were 5–40% more than those using all of the retained features. The feasibility of the cortical features for the recognition of anatomical patterns was certified; thus, the proposed method has the potential to improve the clinical diagnosis of sub-types of MCI and predict the risk of its conversion to Alzheimer's disease

Quantitative 18F-AV1451 Brain Tau PET Imaging in Cognitively Normal Older Adults, Mild Cognitive Impairment, and Alzheimer's Disease Patients

Recent developments of tau Positron Emission Tomography (PET) allows assessment of regional neurofibrillary tangles (NFTs) deposition in human brain. Among the tau PET molecular probes, 18F-AV1451 is characterized by high selectivity for pathologic tau aggregates over amyloid plaques, limited non-specific binding in white and gray matter, and confined off-target binding. The objectives of the study are (1) to quantitatively characterize regional brain tau deposition measured by 18F-AV1451 PET in cognitively normal older adults (CN), mild cognitive impairment (MCI), and AD participants; (2) to evaluate the correlations between cerebrospinal fluid (CSF) biomarkers or Mini-Mental State Examination (MMSE) and 18F-AV1451 PET standardized uptake value ratio (SUVR); and (3) to evaluate the partial volume effects on 18F-AV1451 brain uptake.Methods: The study included total 115 participants (CN = 49, MCI = 58, and AD = 8) from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Preprocessed 18F-AV1451 PET images, structural MRIs, and demographic and clinical assessments were downloaded from the ADNI database. A reblurred Van Cittertiteration method was used for voxelwise partial volume correction (PVC) on PET images. Structural MRIs were used for PET spatial normalization and region of interest (ROI) definition in standard space. The parametric images of 18F-AV1451 SUVR relative to cerebellum were calculated. The ROI SUVR measurements from PVC and non-PVC SUVR images were compared. The correlation between ROI 18F-AV1451 SUVR and the measurements of MMSE, CSF total tau (t-tau), and phosphorylated tau (p-tau) were also assessed.Results:18F-AV1451 prominently specific binding was found in the amygdala, entorhinal cortex, parahippocampus, fusiform, posterior cingulate, temporal, parietal, and frontal brain regions. Most regional SUVRs showed significantly higher uptake of 18F-AV1451 in AD than MCI and CN participants. SUVRs of small regions like amygdala, entorhinal cortex and parahippocampus were statistically improved by PVC in all groups (p &lt; 0.01). Although there was an increasing tendency of 18F-AV-1451 SUVRs in MCI group compared with CN group, no significant difference of 18F-AV1451 deposition was found between CN and MCI brains with or without PVC (p &gt; 0.05). Declined MMSE score was observed with increasing 18F-AV1451 binding in amygdala, entorhinal cortex, parahippocampus, and fusiform. CSF p-tau was positively correlated with 18F-AV1451 deposition. PVC improved the results of 18F-AV-1451 tau deposition and correlation studies in small brain regions.Conclusion: The typical deposition of 18F-AV1451 tau PET imaging in AD brain was found in amygdala, entorhinal cortex, fusiform and parahippocampus, and these regions were strongly associated with cognitive impairment and CSF biomarkers. Although more deposition was observed in MCI group, the 18F-AV-1451 PET imaging could not differentiate the MCI patients from CN population. More tau deposition related to decreased MMSE score and increased level of CSF p-tau, especially in ROIs of amygdala, entorhinal cortex and parahippocampus. PVC did improve the results of tau deposition and correlation studies in small brain regions and suggest to be routinely used in 18F-AV1451 tau PET quantification

The Effect of Latency Reversal Agents on Primary CD8 + T Cells: Implications for Shock and Kill Strategies for Human Immunodeficiency Virus Eradication

Shock and kill strategies involving the use of small molecules to induce viral transcription in resting CD4 + T cells (shock) followed by immune mediated clearance of the reactivated cells (kill), have been proposed as a method of eliminating latently infected CD4 + T cells. The combination of the histone deacetylase (HDAC) inhibitor romidepsin and protein kinase C (PKC) agonist bryostatin-1 is very effective at reversing latency in vitro. However, we found that primary HIV-1 specific CD8 + T cells were not able to eliminate autologous resting CD4 + T cells that had been reactivated with these drugs. We tested the hypothesis that the drugs affected primary CD8 + T cell function and found that both agents had inhibitory effects on the suppressive capacity of HIV-specific CD8 + T cells from patients who control viral replication without antiretroviral therapy (elite suppressors/controllers). The inhibitory effect was additive and multi-factorial in nature. These inhibitory effects were not seen with prostratin, another PKC agonist, either alone or in combination with JQ1, a bromodomain-containing protein 4 inhibitor. Our results suggest that because of their adverse effects on primary CD8 + T cells, some LRAs may cause immune-suppression and therefore should be used with caution in shock and kill strategies

The Effect of Latency Reversal Agents on Primary CD8+ T Cells: Implications for Shock and Kill Strategies for Human Immunodeficiency Virus Eradication

Shock and kill strategies involving the use of small molecules to induce viral transcription in resting CD4+ T cells (shock) followed by immune mediated clearance of the reactivated cells (kill), have been proposed as a method of eliminating latently infected CD4+ T cells. The combination of the histone deacetylase (HDAC) inhibitor romidepsin and protein kinase C (PKC) agonist bryostatin-1 is very effective at reversing latency in vitro. However, we found that primary HIV-1 specific CD8+ T cells were not able to eliminate autologous resting CD4+ T cells that had been reactivated with these drugs. We tested the hypothesis that the drugs affected primary CD8+ T cell function and found that both agents had inhibitory effects on the suppressive capacity of HIV-specific CD8+ T cells from patients who control viral replication without antiretroviral therapy (elite suppressors/controllers). The inhibitory effect was additive and multi-factorial in nature. These inhibitory effects were not seen with prostratin, another PKC agonist, either alone or in combination with JQ1, a bromodomain-containing protein 4 inhibitor. Our results suggest that because of their adverse effects on primary CD8+ T cells, some LRAs may cause immune-suppression and therefore should be used with caution in shock and kill strategies

Diversity of species and genera found within different honey bee colony environments.

<p>(A) Venn diagram representation of species-level diversity (97% identity) of the active bacterial communities that were found within three bee-associated sampling environments (bee bread, bee guts, and whole bees), pooled across colony type. The total species richness in the dataset was 1,019 OTUs, with the most species-rich environment being bee guts (824 total species). (B) The core microbiota among all three environments included 103 species that spanned 26 genera, with <i>Oenococcus</i> and <i>Succinivibrionaceae</i> comprising the largest fractions.</p