Controlling HIV-1: Non-Coding RNA Gene Therapy Approaches to a Functional Cure

Novel siRNA therapeutics demonstrate multi-variant efficacy against SARS-CoV-2

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a respiratory virus that causes COVID-19 disease, with an estimated global mortality of approximately 2%. While global response strategies, which are predominantly reliant on regular vaccinations, have shifted from zero COVID to living with COVID, there is a distinct lack of broad-spectrum direct acting antiviral therapies that maintain efficacy across evolving SARS-CoV-2 variants of concern. This is of most concern for immunocompromised and immunosuppressed individuals who lack robust immune responses following vaccination, and others at risk for severe COVID and long-COVID. RNA interference (RNAi) therapeutics induced by short interfering RNAs (siRNAs) offer a promising antiviral treatment option, with broad-spectrum antiviral capabilities unparalleled by current antiviral therapeutics and a high genetic barrier to antiviral escape. Here we describe novel siRNAs, targeting highly conserved regions of the SARS-CoV-1 and 2 genome of both human and animal species, with multi-variant antiviral potency against eight SARS-CoV-2 lineages - Ancestral VIC01, Alpha, Beta, Gamma, Delta, Zeta, Kappa and Omicron. Treatment with our siRNA resulted in significant protection against virus-mediated cell death in vitro, with >97% cell survival (P < 0.0001), and corresponding reductions of viral nucleocapsid RNA of up to 99.9% (P < 0.0001). When compared to antivirals; Sotrovimab and Remdesivir, the siRNAs demonstrated a more potent antiviral effect and similarly, when multiplexing siRNAs to target different viral regions simultaneously, an increased antiviral effect was observed compared to individual siRNA treatments (P < 0.0001). These results demonstrate the potential for a highly effective broad-spectrum direct acting antiviral against multiple SARS-CoV-2 variants, including variants resistant to antivirals and vaccine generated neutralizing antibodies.

Layer-by-Layer Particles Deliver Epigenetic Silencing siRNA to HIV-1 Latent Reservoir Cell Types

For over two decades, nanomaterials have been employed to facilitate intracellular delivery of small interfering RNA (siRNA), both in vitro and in vivo, to induce post-transcriptional gene silencing (PTGS) via RNA interference. Besides PTGS, siRNAs are also capable of transcriptional gene silencing (TGS) or epigenetic silencing, which targets the gene promoter in the nucleus and prevents transcription via repressive epigenetic modifications. However, silencing efficiency is hampered by poor intracellular and nuclear delivery. Here, polyarginine-terminated multilayered particles are reported as a versatile system for the delivery of TGS-inducing siRNA to potently suppress virus transcription in HIV-infected cells. siRNA is complexed with multilayered particles formed by layer-by-layer assembly of poly(styrenesulfonate) and poly(arginine) and incubated with HIV-infected cell types, including primary cells. Using deconvolution microscopy, uptake of fluorescently labeled siRNA is observed in the nuclei of HIV-1 infected cells. Viral RNA and protein are measured to confirm functional virus silencing from siRNA delivered using particles 16 days post-treatment. This work extends conventional particle-enabled PTGS siRNA delivery to the TGS pathway and paves the way for future studies on particle-delivered siRNA for efficient TGS of various diseases and infections, including HIV.

Impacts of Binary Oxide Nanoparticles on the Soybean Plant and Its Rhizosphere, Associated Phytohormones, and Enzymes

The utilization of binary oxide nanoparticles is geometrically increasing due to their numerous applications. Their intentional or accidental release after usage has led to their omnipresence in the environment. The usage of sludge or fertilizer containing binary oxide nanoparticles is likely to increase the chance of the plants being exposed to these binary oxide nanoparticles. The aim of the present review is to assess the detailed positive and negative impacts of these oxide nanoparticles on the soybean plants and its rhizosphere. In this study, methods of synthesizing binary oxide nanoparticles, as well as the merits and demerits of these methods, are discussed. Furthermore, various methods of characterizing the binary oxide nanoparticles in the tissues of soybean are highlighted. These characterization techniques help to track the nanoparticles inside the soybean plant. In addition, the assessment of rhizosphere microbial communities of soybean that have been exposed to these binary oxide nanoparticles is discussed. The impacts of binary oxide nanoparticles on the leaf, stem, root, seeds, and rhizosphere of soybean plant are comprehensively discussed. The impacts of binary oxides on the bioactive compounds such as phytohormones are also highlighted. Overall, it was observed that the impacts of the oxide nanoparticles on the soybean, rhizosphere, and bioactive compounds were dose-dependent. Lastly, the way forward on research involving the interactions of binary oxide nanoparticles and soybean plants is suggested.

Evolving Strategies to Eliminate the CD4 T Cells HIV Viral Reservoir via CAR T Cell Immunotherapy

Although the advent of ART has significantly reduced the morbidity and mortality associated with HIV infection, the stable pool of HIV in latently infected cells requires lifelong treatment adherence, with the cessation of ART resulting in rapid reactivation of the virus and productive HIV infection. Therefore, these few cells containing replication-competent HIV, known as the latent HIV reservoir, act as the main barrier to immune clearance and HIV cure. While several strategies involving HIV silencing or its reactivation in latently infected cells for elimination by immune responses have been explored, exciting cell based immune therapies involving genetically engineered T cells expressing synthetic chimeric receptors (CAR T cells) are highly appealing and promising. CAR T cells, in contrast to endogenous cytotoxic T cells, can function independently of MHC to target HIV-infected cells, are efficacious and have demonstrated acceptable safety profiles and long-term persistence in peripheral blood. In this review, we present a comprehensive picture of the current efforts to target the HIV latent reservoir, with a focus on CAR T cell therapies. We highlight the current challenges and advances in this field, while discussing the importance of novel CAR designs in the efforts to find a HIV cure.

The Versatility in the Applications of Dithiocarbamates

Dithiocarbamate ligands have the ability to form stable complexes with transition metals, and this chelating ability has been utilized in numerous applications. The complexes have also been used to synthesize other useful compounds. Here, the up-to-date applications of dithiocarbamate ligands and complexes are extensively discussed. Some of these are their use as enzyme inhibitor and treatment of HIV and other diseases. The application as anticancer, antimicrobial, medical imaging and anti-inflammatory agents is examined. Moreover, the application in the industry as vulcanization accelerator, froth flotation collector, antifouling, coatings, lubricant additives and sensors is discussed. The various ways in which they have been employed in synthesis of other compounds are highlighted. Finally, the agricultural uses and remediation of heavy metals via dithiocarbamate compounds are comprehensively discussed.

Long Non-coding RNAs, Lnc(ing) RNA Metabolism to Cancer Biology

The eukaryotic genome is represented by a vast proportion of non-coding regions, which in recent years have been attributed to have important functional roles in gene regulation through a myriad of processes, ranging from proper localization, correct folding and, most importantly, spatial and temporally regulated expression of genes. One of the major contributing factors in these processes is ribonucleic acid (RNA) metabolism, which comprises the RNA-nucleoprotein (RNP) complexes that interact with and instruct the genome to function. Long non-coding RNAs are an integral component of several RNPs, and herein we provide an overview of the understanding of the long non-coding RNAs, their characteristics, their function and their balancing act as dual modulators in cancer manifestation and progression.

Could gene therapy cure HIV?

The Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS) continues to be a major global public health issue, having claimed almost 33 million lives so far. According to the recent report of the World Health Organization (WHO) in 2019, about 38 million people are living with AIDS. Hence, finding a solution to overcome this life-threatening virus can save millions of lives. Scientists and medical doctors have prescribed HIV patients with specific drugs for many years. Methods such antiretroviral therapy (ART) or latency-reversing agents (LRAs) have been used for a while to treat HIV patients, however they have some side effects and drawbacks causing their application to be not quite successful. Instead, the application of gene therapy which refers to the utilization of the therapeutic delivery of nucleic acids into a patient's cells as a drug to treat disease has shown promising results to control HIV infection. Therefore, in this review, we will summarize recent advances in gene therapy approach against HIV.

RNAi therapeutics: an antiviral strategy for human infections

Gene silencing induced by RNAi represents a promising antiviral development strategy. This review will summarise the current state of RNAi therapeutics for treating acute and chronic human virus infections. The gene silencing pathways exploited by RNAi therapeutics will be described and include both classic RNAi, inducing cytoplasmic mRNA degradation post-transcription and novel RNAi, mediating epigenetic modifications at the transcription level in the nucleus. Finally, the challenge of delivering gene modifications via RNAi will be discussed, along with the unique characteristics of respiratory versus systemic administration routes to highlight recent advances and future potential of RNAi antiviral treatment strategies.

Gene Therapy Approaches to Functional Cure and Protection of Hematopoietic Potential in HIV Infection

Although current antiretroviral drug therapy can suppress the replication of human immunodeficiency virus (HIV), a lifelong prescription is necessary to avoid viral rebound. The problem of persistent and ineradicable viral reservoirs in HIV-infected people continues to be a global threat. In addition, some HIV-infected patients do not experience sufficient T-cell immune restoration despite being aviremic during treatment. This is likely due to altered hematopoietic potential. To achieve the global eradication of HIV disease, a cure is needed. To this end, tremendous efforts have been made in the field of anti-HIV gene therapy. This review will discuss the concepts of HIV cure and relative viral attenuation and provide an overview of various gene therapy approaches aimed at a complete or functional HIV cure and protection of hematopoietic functions.

Transcriptional gene silencing limits CXCR4-associated depletion of bone marrow CD34+ cells in HIV-1 infection

OBJECTIVES

Hematological abnormalities that include changes in bone marrow, such as in anemia and pancytopenia, are common among HIV-infected patients, particularly in the advanced stage of disease. Such abnormalities may be caused by a reduced bone marrow function for hematopoiesis. The aim of this study was to determine whether transcriptional gene silencing can help to preserve the hosts' hematopoietic potential in addition to peripheral CD4+ T cells against CCR5-tropic HIV infection.

DESIGN

NOD/SCID/JAK3null (NOJ) mice were transplanted with human cord-derived CD34+ cells with or without transduction with a lentiviral vector expressing a promoter-targeting shRNA called PromA.

METHODS

At 16 weeks after transplantation, mice engrafted with CD34+ cells were infected with CCR5-tropic HIV-1JRFL.

RESULTS

At week 2 postinfection, HIV replication was observed in peripheral blood mononuclear cells and splenocytes. In mice transplanted with unmanipulated CD34+ cells, viral replication was accompanied by a loss of peripheral/spleen CD4+CCR5+ T cells. Interestingly, bone marrow CD34+ cells in HIV-infected mice were also depleted, but in a CXCR4-associated manner. Conversely, the lentiviral transfer of PromA in CD34+ cells prior to transplantation rendered the humanized NOJ mice resistant to HIV replication in CD4+ T cells, resulting in better preservation of peripheral/spleen CD4+CCR5+ T cells and bone marrow CD34+ cells at 2 weeks after infection.

CONCLUSIONS

These results indicate that stable gene transfer of PromA to hematopoietic stem cells not only limited HIV replication but also led to preservation of different subsets of hematopoietic cells, including bone marrow stem/progenitor cells and CD4+ T cells.

Eradication of HIV from Tissue Reservoirs: Challenges for the Cure

The persistence of HIV infection, even after lengthy and successful combined antiretroviral therapy (cART), has precluded an effective cure. The anatomical locations and biological mechanisms through which the viral population is maintained remain unknown. Much research has focused nearly exclusively on circulating resting T cells as the predominant source of persistent HIV, a strategy with limited success in developing an effective cure strategy. In this study, we review research supporting the importance of anatomical tissues and other immune cells for HIV maintenance and expansion, including the central nervous system, lymph nodes, and macrophages. We present accumulated research that clearly demonstrates the limitations of using blood-derived cells as a proxy for tissue reservoirs and sanctuaries throughout the body. We cite recent studies that have successfully used deep-sequencing strategies to uncover the complexity of HIV infection and the ability of the virus to evolve despite undetectable plasma viral loads. Finally, we suggest new strategies and highlight the importance of tissue banks for future research.

Engineering hematopoietic stem cells toward a functional cure of human immunodeficiency virus infection

The battle with human immunodeficiency virus (HIV) has been ongoing for more than 30 years, and although progress has been made, there are still significant challenges remaining. A few unique features render HIV to be one of the toughest viruses to conquer in the modern medicine era, such as the ability to target the host immune system, persist by integrating into the host genome and adapt to a hostile environment such as a single anti-HIV medication by continuously evolving. The finding of combination anti-retroviral therapy (cART) about 2 decades ago has transformed the treatment options for HIV-infected patients and significantly improved patient outcomes. However, finding an HIV cure has proven to be extremely challenging with the only known exception being the so-called "Berlin patient," whose immune system was replaced by stem cell transplants from a donor missing one of HIV's key co-receptors (CCR5). The broad application of this approach is limited by the requirement of an HLA-matched donor who is also homozygous for the rare CCR5 delta32 deletion. On the other hand, the Berlin patient provided the proof of concept of a potential cure for HIV using HIV-resistant hematopoietic stem cells (HSCs), revitalizing the hope to find an HIV cure that is broadly applicable. Here we will review strategies and recent attempts to engineer HIV-resistant HSCs as a path to an HIV cure.

Can We Repurpose FDA-Approved Alefacept to Diminish the HIV Reservoir?

Current anti-retroviral treatment (ART) for HIV is effective in maintaining HIV at undetectable levels. However, cessation of ART results in immediate and brisk rebound of viremia to high levels. This rebound is driven by an HIV reservoir mainly enriched in memory CD4+ T cells. In order to provide any form of functional HIV Cure, elimination of this viral reservoir has become the focus of current HIV cure strategies. Alefacept was initially developed for the treatment of chronic plaque psoriasis. Alefacept is a chimeric fusion protein consisting of the CD2-binding portion of human leukocyte function antigen-3 (LFA3) linked to the Fc region of human IgG1 (LFA3-Fc). Alefacept was designed to inhibit memory T cell activation that contributes to the chronic autoimmune disease psoriasis by blocking the CD2 coreceptor. However, it was found to deplete memory T cells that express high levels of CD2 via NK cell-mediated antibody dependent cell cytotoxicity (ADCC) in vivo. Phase II and phase III clinical trials of alefacept with psoriasis patients demonstrated promising results and an excellent safety profile. Subsequently, alefacept has been successfully repurposed for other memory T cell-mediated autoimmune diseases including skin diseases other than psoriasis, organ transplantation and type I diabetes (T1D). Herein, we review our specific strategy to repurpose the FDA approved biologic alefacept to decrease and hopefully someday eliminate the HIV reservoir, for which CD2hi memory CD4+ T cells are a significant contributor.