Sridhar Selvaraj

All Publications

• Human striatal progenitor cells that contain inducible safeguards and overexpress BDNF rescue Huntington's disease phenotypes. Molecular therapy. Methods & clinical development Simmons, D. A., Selvaraj, S., Chen, T., Cao, G., Camelo, T. S., McHugh, T. L., Gonzalez, S., Martin, R. M., Simanauskaite, J., Uchida, N., Porteus, M. H., Longo, F. M. 2025; 33 (1): 101415

  Abstract

  Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder characterized by striatal atrophy. Reduced trophic support due to decreased striatal levels of neurotrophins (NTs), mainly brain-derived neurotrophic factor (BDNF), contributes importantly to HD pathogenesis; restoring NTs has significant therapeutic potential. Human pluripotent stem cells (hPSCs) offer a scalable platform for NT delivery but have potential safety risks including teratoma formation. We engineered hPSCs to constitutively produce BDNF and contain inducible safeguards to eliminate these cells if safety concerns arise. This study examined the efficacy of intrastriatally transplanted striatal progenitor cells (STRpcs) derived from these hPSCs against HD phenotypes in R6/2 mice. Engrafted STRpcs overexpressing BDNF alleviated motor and cognitive deficits and reduced mutant huntingtin aggregates. Activating the inducible safety switch with rapamycin safely eliminated the engrafted cells. These results demonstrate that BDNF delivery via a novel hPSC-based platform incorporating safety switches could be a safe and effective HD therapeutic.

  View details for DOI 10.1016/j.omtm.2025.101415

  View details for PubMedID 39995448

  View details for PubMedCentralID PMC11848452

• Human striatal progenitor cells that contain inducible safeguards and overexpress BDNF rescue Huntington's disease phenotypes MOLECULAR THERAPY METHODS & CLINICAL DEVELOPMENT Simmons, D. A., Selvaraj, S., Chen, T., Cao, G., Camelo, T., Mchugh, T. M., Gonzalez, S., Martin, R. M., Simanauskaite, J., Uchida, N., Porteus, M. H., Longo, F. M. 2025; 33 (1)

  View details for DOI 10.1016/j.omtm.2025.101415

  View details for Web of Science ID 001424116600001

• Engineering synthetic signaling receptors to enable erythropoietin-free erythropoiesis. Nature communications Shah, A. P., Majeti, K. R., Ekman, F. K., Selvaraj, S., Sharma, D., Sinha, R., Soupene, E., Chati, P., Luna, S. E., Charlesworth, C. T., McCreary, T., Lesch, B. J., Tran, T., Chu, S. N., Porteus, M. H., Kyle Cromer, M. 2025; 16 (1): 1140

  Abstract

  Blood transfusion plays a vital role in modern medicine, but frequent shortages occur. Ex vivo manufacturing of red blood cells (RBCs) from universal donor cells offers a potential solution, yet the high cost of recombinant cytokines remains a barrier. Erythropoietin (EPO) signaling is crucial for RBC development, and EPO is among the most expensive media components. To address this challenge, we develop highly optimized small molecule-inducible synthetic EPO receptors (synEPORs) using design-build-test cycles and genome editing. By integrating synEPOR at the endogenous EPOR locus in O-negative induced pluripotent stem cells, we achieve equivalent erythroid differentiation, transcriptomic changes, and hemoglobin production using small molecules compared to EPO-supplemented cultures. This approach dramatically reduces culture media costs. Our strategy not only addresses RBC production challenges but also demonstrates how protein and genome engineering can introduce precisely regulated cellular behaviors, potentially improving scalable manufacturing of a wide range of clinically relevant cell types.

  View details for DOI 10.1038/s41467-025-56239-5

  View details for PubMedID 39880867

  View details for PubMedCentralID 5355882

• Human assembloids reveal the consequences of CACNA1G gene variants in the thalamocortical pathway. Neuron Kim, J. I., Miura, Y., Li, M. Y., Revah, O., Selvaraj, S., Birey, F., Meng, X., Thete, M. V., Pavlov, S. D., Andersen, J., Pașca, A. M., Porteus, M. H., Huguenard, J. R., Pașca, S. P. 2024

  Abstract

  Abnormalities in thalamocortical crosstalk can lead to neuropsychiatric disorders. Variants in CACNA1G, which encodes the α1G subunit of the thalamus-enriched T-type calcium channel, are associated with absence seizures, intellectual disability, and schizophrenia, but the cellular and circuit consequences of these genetic variants in humans remain unknown. Here, we developed a human assembloid model of the thalamocortical pathway to dissect the contribution of genetic variants in T-type calcium channels. We discovered that the M1531V CACNA1G variant associated with seizures led to changes in T-type currents in thalamic neurons, as well as correlated hyperactivity of thalamic and cortical neurons in assembloids. By contrast, CACNA1G loss, which has been associated with risk of schizophrenia, resulted in abnormal thalamocortical connectivity that was related to both increased spontaneous thalamic activity and aberrant axonal projections. These results illustrate the utility of multi-cellular systems for interrogating human genetic disease risk variants at both cellular and circuit level.

  View details for DOI 10.1016/j.neuron.2024.09.020

  View details for PubMedID 39419023

• Enhancement of erythropoietic output by Cas9-mediated insertion of a natural variant in haematopoietic stem and progenitor cells. Nature biomedical engineering Luna, S. E., Camarena, J., Hampton, J. P., Majeti, K. R., Charlesworth, C. T., Soupene, E., Selvaraj, S., Jia, K., Sheehan, V. A., Cromer, M. K., Porteus, M. H. 2024

  Abstract

  Some gene polymorphisms can lead to monogenic diseases, whereas other polymorphisms may confer beneficial traits. A well-characterized example is congenital erythrocytosis-the non-pathogenic hyper-production of red blood cells-that is caused by a truncated erythropoietin receptor. Here we show that Cas9-mediated genome editing in CD34+ human haematopoietic stem and progenitor cells (HSPCs) can recreate the truncated form of the erythropoietin receptor, leading to substantial increases in erythropoietic output. We also show that combining the expression of the cDNA of a truncated erythropoietin receptor with a previously reported genome-editing strategy to fully replace the HBA1 gene with an HBB transgene in HSPCs (to restore normal haemoglobin production in cells with a β-thalassaemia phenotype) gives the edited HSPCs and the healthy red blood cell phenotype a proliferative advantage. Combining knowledge of human genetics with precise genome editing to insert natural human variants into therapeutic cells may facilitate safer and more effective genome-editing therapies for patients with genetic diseases.

  View details for DOI 10.1038/s41551-024-01222-6

  View details for PubMedID 38886504

  View details for PubMedCentralID 46538

• Improving Therapeutic Homology Directed Repair Genome Editing Efficiency in Human Primary Cells through Optimal Guide RNA Selection Selvaraj, S., Johnston, N., Schmiderer, L., Amorin, N. A., Porteus, M. H. CELL PRESS. 2024: 359-360

  View details for Web of Science ID 001332783401306

• Further Investigation of HBB Gene Editing with CRISPR/Cas9/rAAV6 in Human HSPCs to Treat Sickle Cell Disease Xu, L., Selvaraj, S., Porteus, M. H. CELL PRESS. 2024: 555

  View details for Web of Science ID 001332783402095

• High-efficiency transgene integration by homology-directed repair in human primary cells using DNA-PKcs inhibition. Nature biotechnology Selvaraj, S., Feist, W. N., Viel, S., Vaidyanathan, S., Dudek, A. M., Gastou, M., Rockwood, S. J., Ekman, F. K., Oseghale, A. R., Xu, L., Pavel-Dinu, M., Luna, S. E., Cromer, M. K., Sayana, R., Gomez-Ospina, N., Porteus, M. H. 2023

  Abstract

  Therapeutic applications of nuclease-based genome editing would benefit from improved methods for transgene integration via homology-directed repair (HDR). To improve HDR efficiency, we screened six small-molecule inhibitors of DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a key protein in the alternative repair pathway of non-homologous end joining (NHEJ), which generates genomic insertions/deletions (INDELs). From this screen, we identified AZD7648 as the most potent compound. The use of AZD7648 significantly increased HDR (up to 50-fold) and concomitantly decreased INDELs across different genomic loci in various therapeutically relevant primary human cell types. In all cases, the ratio of HDR to INDELs markedly increased, and, in certain situations, INDEL-free high-frequency (>50%) targeted integration was achieved. This approach has the potential to improve the therapeutic efficacy of cell-based therapies and broaden the use of targeted integration as a research tool.

  View details for DOI 10.1038/s41587-023-01888-4

  View details for PubMedID 37537500

  View details for PubMedCentralID 3694601

• Delivery of BDNF through a Pluripotent Stem Cell-Based Platform Ameliorates Behavioral Deficits in a Mouse Model of Huntington's Disease Selvaraj, S., Simmons, D. A., Chen, T., Cao, G. Y., Camelo, T. S., McHugh, T. M., Gonzalez, S., Martin, R. M., Simanauskaite, J. M., Uchida, N., Longo, F. M., Porteus, M. H. CELL PRESS. 2023: 18

  View details for Web of Science ID 001045144200034

• Measuring Small Molecule Improvements in Genome Editing for Pyruvate Kinase Deficiency Using DNA Barcoding Templates Ojeda Perez, I., Selvaraj, S., Bustos, A., Javier Serrano, L., Bonafont, J., Alberquilla-Fernandez, O., Amorin, N. A., Garcia-Torralba, A., Torres-Ruiz, R., Rodriguez-Perales, S., Trigueros, C., Mayo-Garcia, R., Quintana-Bustamante, O., Sanchez-Dominguez, R., Porteus, M. H., Carlos Segovia, J. CELL PRESS. 2023: 540

  View details for Web of Science ID 001045144202311

• GMEB2 is a Conserved Cellular AAV Restriction Factor That Inhibits Transduction of Human Stem Cells Dudek, A. M., Johnston, N. M., Vaidyanathan, S., Selvaraj, S., Porteus, M. H. CELL PRESS. 2021: 48-49

  View details for Web of Science ID 000645188700095