Publications by authors named "Srujan Marepally"

Background: Sickle cell disease (SCD) and β-thalassemia patients with elevated gamma globin (HBG1/G2) levels exhibit mild or no symptoms. To recapitulate this natural phenomenon, the most coveted gene therapy approach is to edit the regulatory sequences of HBG1/G2 to reactivate them. By editing more than one regulatory sequence in the HBG promoter, the production of fetal hemoglobin (HbF) can be significantly increased.

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/: Hemophilia B is a hereditary bleeding disorder due to the production of liver malfunctional factor IX (FIX). Gene therapy with viral vectors offers a cure. However, applications are limited due to pre-existing antibodies, eligibility for children under 12 years of age, hepatotoxicity, and excessive costs.

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Article Synopsis
  • Recent studies indicate that base editing can cause significant deletions in specific gene regions, which may reduce its therapeutic effectiveness even when fewer deletions occur compared to traditional Cas9 methods.
  • The research explores using a dCas9 fusion of ABE8e instead of nickaseCas9 to maintain editing efficiency while minimizing these deletions in human hematopoietic stem and progenitor cells (HSPCs).
  • Findings reveal that dABE8e allows for effective editing without creating large deletions, leading to a safer method for genome editing with improved precision.
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The suboptimal efficacies of existing anti-malarial drugs attributed to the emergence of drug resistance dampen the clinical outcomes. Hence, there is a need for developing novel drug and drug targets. Recently silver nanoparticles (AgNPs) constructed with the leaf extracts of Euphorbia cotinifolia were shown to possess antimalarial activity.

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Article Synopsis
  • Hemophilia A (HemA) requires regular factor VIII protein infusions, but new modified mRNA therapies could reduce the need for frequent treatments and enhance safety.
  • Researchers experimented with various base modifications in mRNA, finding that -methyl pseudouridine significantly boosts translation efficiency in liver and endothelial cells.
  • The study's mΨ modified functional FVIII mRNA, delivered via a liver-targeted lipid nanoparticle, demonstrated high therapeutic efficacy in HemA mouse models, suggesting a promising approach for treating genetic liver disorders.
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Inherited genetic disorders of the liver pose a significant public health burden. Liver transplantation is often limited by the availability of donor livers and the exorbitant costs of immunosuppressive therapy. To overcome these limitations, nucleic acid therapy provides a hopeful alternative that enables gene repair, gene supplementation, and gene silencing with suitable vectors.

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β-thalassemia/HbE results from mutations in the β-globin locus that impede the production of functional adult hemoglobin. Base editors (BEs) could facilitate the correction of the point mutations with minimal or no indel creation, but its efficiency and bystander editing for the correction of β-thalassemia mutations in coding and non-coding regions remains unexplored. Here, we screened BE variants in HUDEP-2 cells for their ability to correct a spectrum of β-thalassemia mutations that were integrated into the genome as fragments of .

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Background: Throughout the COVID-19 pandemic, virus evolution and large-scale vaccination programs have caused multiple exposures to SARS CoV-2 spike protein, resulting in complex antibody profiles. The binding of these to spike protein of "future" variants in the context of such heterogeneous exposure has not been studied.

Methods: We tested archival sera (Delta and Omicron period) stratified by anti-spike antibody (including IgG) levels for reactivity to Omicron-subvariants(BA.

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The continual emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants has necessitated the development of broad cross-reactive vaccines. Recent findings suggest that enhanced antigen presentation could lead to cross-reactive humoral responses against the emerging variants. Toward enhancing the antigen presentation to dendritic cells (DCs), we developed a novel shikimoylated mannose receptor targeting lipid nanoparticle (SMART-LNP) system that could effectively deliver mRNAs into DCs.

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BCL11A-XL directly binds and represses the fetal globin (HBG1/2) gene promoters, using 3 zinc-finger domains (ZnF4, ZnF5, and ZnF6), and is a potential target for β-hemoglobinopathy treatments. Disrupting BCL11A-XL results in derepression of fetal globin and high HbF, but also affects hematopoietic stem and progenitor cell (HSPC) engraftment and erythroid maturation. Intriguingly, neurodevelopmental patients with ZnF domain mutations have elevated HbF with normal hematological parameters.

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Advancements in gene delivery and editing have expanded the applications of autologous hematopoietic stem and progenitor cells (HSPCs) for the treatment of monogenic and acquired diseases. The gene editing toolbox is growing, and the ability to achieve gene editing with mRNA or protein delivered intracellularly by vehicles, such as electroporation and nanoparticles, has highlighted the potential of gene editing in HSPCs. Ongoing phase I/II clinical trials with gene-edited HSPCs for β-hemoglobinopathies provide hope for treating monogenic diseases.

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Spike glycoprotein of SARS-CoV-2 variants plays a critical role in infection and transmission through its interaction with human angiotensin converting enzyme 2 (hACE2) receptors. Prior findings using molecular docking and biomolecular studies reported varied findings on the difference in the interactions among the spike variants with the hACE2 receptors. Hence, it is a prerequisite to understand these interactions in a more precise manner.

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Reactivation of fetal hemoglobin (HbF) is a commonly adapted strategy to ameliorate β-hemoglobinopathies. However, the continued production of defective adult hemoglobin (HbA) limits HbF tetramer production affecting the therapeutic benefits. Here, we evaluated deletional hereditary persistence of fetal hemoglobin (HPFH) mutations and identified an 11-kb sequence, encompassing putative repressor region (PRR) to β-globin exon-1 (βE1), as the core deletion that ablates HbA and exhibits superior HbF production compared with HPFH or other well-established targets.

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The CRISPR/Cas9 system holds great promise in treating genetic diseases, owing to its safe and precise genome editing. However, the major challenges to implementing the technology in clinics lie in transiently limiting the expression of genome editing factors and achieving therapeutically relevant frequencies with fidelity. Recent findings revealed that non-viral vectors could be a potential alternative delivery system to overcome these limitations.

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Sickle cell anaemia (SCA) is one of the common autosomal recessive monogenic disorders, caused by a transverse point mutation (GAG > GTG) at the sixth codon of the beta-globin gene, which results in haemolytic anaemia due to the fragile RBCs. Recent progress in genome editing has gained attention for the therapeutic cure for SCA. Direct correction of SCA mutation by homology-directed repair relies on a double-strand break (DSB) at the target site and carries the risk of generating beta-thalassaemic mutations if the editing is not error-free.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission in India in 2020-2022 was driven predominantly by Wild (Wuhan-Hu-1 and D614G), Delta, and Omicron variants. The aim of this study was to examine the effect of infections on the humoral immune response and cross-reactivity to spike proteins of Wuhan-Hu-1, Delta, C.1.

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In recent years, chemically modified messenger RNA (mRNA) has emerged as a potent nucleic acid molecule for developing a wide range of therapeutic applications, including a novel class of vaccines, protein replacement therapies, and immune therapies. Among delivery vectors, lipid nanoparticles are found to be safer and more effective in delivering RNA molecules (e.g.

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Lipid-enabled nucleic acid delivery has garnered tremendous attention in recent times. Tocopherol among the cationic lipids, 3b-[-(','-dimethylamino-ethane)carbamoyl]-cholesterol hydrochloride (DC-Chol) with a headgroup of dimethylammonium, and cholesterol as a hydrophobic moiety are found to be some of the most successful lipids and are being used in clinical trials. However, limited efficacy is a major limitation for their broader therapeutic application.

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Due to the fast mutating nature of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the development of novel therapeutics, vaccines, and evaluating the efficacies of existing one's against the mutated strains is critical for containing the virus. Pseudotyped SARS-CoV-2 viruses are proven to be instrumental in evaluating the efficiencies of therapeutics, owing to their ease in application and safety when compared to handling the live virus. However, a comprehensive protocol that includes selecting transfection reagents, validating different packaging systems for high-throughput screening of neutralizing antibodies, is still a requisite.

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Transplantation of allogenic hematopoietic stem and progenitor cells (HSPCs) with C-C chemokine receptor type 5 (CCR5) Δ32 genotype generates HIV-1 resistant immune cells. CCR5 gene edited autologous HSPCs can be a potential alternative to hematopoietic stem cell transplantation (HSCT) from HLA-matched CCR5 null donor. However, the clinical application of gene edited autologous HSPCs is critically limited by the quality of the graft, as HIV also infects the HSPCs.

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