Biology subjects

Macedo, A.

Publications and source records attributed to Macedo, A..

5 recordsLinked to original sources

bioRxiv2021

The HIV latency reversal agent HODHBt enhances NK Cell effector and memory-like functions by increasing IL-15 mediated-STAT activation

Elimination of latent HIV reservoirs is a critical endpoint to eradicate HIV. One therapeutic intervention against latent HIV is shock and kill. This strategy is based on the transcriptional activation of latent HIV with a Latency-Reversing Agent (LRA) with the consequent killing of the reactivated cell by either the cytopathic effect of HIV or the immune system. We have previously found that the small molecule 3-Hydroxy-1,2,3-benzotriazin-4(3H)-one (HODHBt) act as an LRA by increasing Signal Transducers and Activators of Transcription (STAT) activation mediated by IL-15 in cells isolated from aviremic participants. The IL-15 superagonist (N-803) is currently under clinical investigation to eliminate latent reservoirs. IL-15 and N-803 share similar mechanism of action by promoting the activation STATs and have shown some promise in pre-clinical models directed towards HIV eradication. In this work, we evaluated the ability of HODHBt to enhance IL-15 signaling in NK cells and the biological consequences associated with increased STAT activation in NK effector and memory-like functions. We showed that HODHBt increased IL-15-mediated STAT phosphorylation in NK cells, resulting in increased secretion of CXCL10 and IFN-{gamma} and expression of cytotoxic proteins including Granzyme B, Granzyme A, Perforin, Granulysin, FASL and TRAIL. This increased cytotoxic profile results in an increase cytotoxicity against different tumor cell lines and HIV-infected cells. HODHBt also improved the generation of cytokine-induced memory-like NK cells. Overall, our data demonstrate that enhancing the magnitude of IL-15 signaling with HODHBt favors NK cell cytotoxicity and memory-like generation, and targeting this pathway could be further explored for HIV cure interventions. Author SummarySeveral clinical trials targeting the HIV latent reservoir with LRAs have been completed. In spite of a lack of clinical benefit of these trials, they have been crucial to elucidate hurdles that shock and kill strategies have to overcome to promote an effective reduction of the latent reservoir leading. These hurdles include low reactivation potential mediated by LRAs; the negative influence of some LRAs on the activity of Natural Killer and CD8T effector cells; an increased resistance to apoptosis of latently infected cells; and an exhausted immune system due to chronic inflammation. To that end, finding therapeutic strategies that can overcome some of these challenges could improve the outcome of shock and kill strategies aimed towards HIV eradication. In here, we showed that the LRA HODHBt also improves IL-15 mediated NK effector and memory-like functions. As such, pharmacological enhancement of IL-15 mediated STAT activation can open new therapeutic venues towards an HIV cure.

cell biology↗

bioRxiv2020

Selective BCL-XLAntagonists Eliminate Infected Cells from a Primary Cell Model of HIV Latency but not from Ex Vivo Reservoirs

HIV persists, despite antiviral immune responses and effective antiretroviral therapy, in viral reservoirs that seed rebound viremia if therapy is interrupted. Previously, we showed that the BCL-2 protein contributes to HIV persistence by conferring a survival advantage to reservoir-harboring cells. Here, we demonstrate that many of the BCL-2 family members are overexpressed in HIV-infected CD4+ T-cells, indicating increased tension between pro-apoptotic and pro-survival family members - as well as raising the possibility that the inhibition of pro-survival members may disproportionately affect the survival of HIV-infected cells. Based on these results, we chose to further study BCL2L1 (encoding the protein BCL-XL), due to its consistent overexpression and the availability of selective antagonists. Infection of primary CD4+ T-cells with either a clinical isolate, a CCR5-tropic strain, or a CXCR4-tropic strain of HIV resulted in increased BCL-XL protein expression; and treatment with two selective BCL-XL antagonists, A-1155463 and A-1551852, led to disproportionate cell death compared to uninfected CD4+ T-cells. In a primary cell model of latency, both BCL-XL antagonists drove significant reductions in total HIV DNA and in infectious cell frequencies both alone and in combination with the latency reversing agent bryostatin-1, with little off-target cytotoxicity. However, these antagonists, with or without bryostatin-1, or in combination with the highly potent latency reversing agent combination PMA + ionomycin, failed to reduce total HIV DNA and infectious reservoirs in ex vivo CD4+ T-cells from ART-suppressed donors. Our results add to growing evidence that bonafide reservoir-harboring cells are resistant to multiple "kick and kill" modalities - relative to latency models - and uncover BCL-XL antagonists as a facile approach to probing mechanistic underpinnings. We also interpret our results as encouraging of further exploration of BCL-XL antagonists for cure, where combination approaches may unlock the ability to eliminate ex vivo reservoirs.

microbiology↗

bioRxiv2020

Innate behavior sequence progression by peptide-mediated interorgan crosstalk

Innate behaviors consist of a succession of genetically-hardwired motor and physiological subprograms that can be coupled to drastic morphogenetic changes. How these integrative responses are orchestrated is not completely understood. Here, we provide insight into these mechanisms by studying pupariation, a multi-step innate behavior of fly larvae that is critical for survival during metamorphosis. We find that the steroid-hormone ecdysone triggers parallel pupariation neuromotor and morphogenetic subprograms, which include the induction of the relaxin-peptide hormone, Dilp8, in the epidermis. Dilp8 acts on six Lgr3-positive thoracic interneurons to couple both subprograms in time and to instruct neuromotor subprogram switching during behavior. Our work reveals that interorgan feedback gates progression between subunits of an innate behavior and points to an ancestral neuromodulatory function of relaxin signaling.

animal behavior and cognition↗

bioRxiv2020

Discrete escape responses are generated by neuropeptide-mediated circuit logic

Animals display a plethora of escape behaviors when faced with environmental threats. Selection of the appropriate response by the underlying neuronal network is key to maximize chances of survival. We uncovered a somatosensory network in Drosophila larvae that encodes two escape behaviors through input-specific neuropeptide action. Sensory neurons required for avoidance of noxious light and escape in response to harsh touch, each converge on discrete domains of the same neuromodulatory hub neurons. These gate harsh touch responses via short Neuropeptide F, but noxious light avoidance via compartmentalized, acute Insulin-like peptide 7 action and cognate Relaxin-family receptor signaling in connected downstream neurons. Peptidergic hub neurons can thus act as central circuit elements for first order processing of converging sensory inputs to gate specific escape responses. One Sentence SummaryCompartment-specific neuropeptide action regulates sensory information processing to elicit discrete escape behavior in Drosophila larvae.

neuroscience↗

bioRxiv2019

The intersectional genetics landscape for human

The human body is made up of hundreds, perhaps thousands of cell types and states, most of which are currently inaccessible genetically. Genetic accessibility carries significant diagnostic and therapeutic potential by allowing the selective delivery of genetic messages or cures to cells. Research in model organisms has shown that single regulatory element (RE) activities are seldom cell type specific, limiting their usage in genetic systems designed to restrict gene expression posteriorly to their delivery to cells. Intersectional genetic approaches can increase the number of genetically accessible cells. A typical intersectional method acts like an AND logic gate by converting the input of two or more active REs into a single synthetic output, which becomes unique for that cell. Here, we systematically assessed the intersectional genetics landscape of human using a curated subset of cells from a large RE usage atlas obtained by Cap Analysis of Gene Expression Sequencing (CAGE-Seq) of thousands of primary and cancer cells (the FANTOM5 consortium atlas). We developed the heuristics and algorithms to retrieve and quality rank AND gate intersections intra- and inter-individually. We find that >90% of the 154 primary cell types surveyed can be distinguished from each other with as little as 3 to 4 active REs, with quantifiable safety and robustness. We call these minimal intersections of active REs with cell-type diagnostic potential "Versatile Entry Codes" (VEnCodes). We show that VEnCodes could be found for 100% of the 158 cancer cell types surveyed, and that most of these are highly robust to intra- and interindividual variation. Our tools for generating and quality-ranking VEnCodes can be adapted to other RE usage databases and to other intersectional methods using alternative Boolean logic operations. Our work demonstrate the potential of intersectional approaches for future gene delivery technologies in human.

bioinformatics↗