Biology subjects

Chen, A. L.

Publications and source records attributed to Chen, A. L..

5 recordsLinked to original sources

bioRxiv2026

HLA-A*11:01-Restricted T Cell Receptors Targeting Mutant NPM1 for Adoptive Cell Therapy in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy associated with a poor prognosis and an unmet need for more effective treatment options, particularly after relapse. One potential approach to address this need, which has been used successfully in solid tumors, is adoptive transfer of T cells engineered to express specific T cell receptors (TCRs). Particularly attractive are TCRs that can target epitopes derived from oncogenes on which cancer cells depend while sparing normal cells that do not harbor the mutation. One promising oncogenic target in AML is mutated nucleophosmin 1 (mtNPM1), present in up to 30% of AML cases. Most NPM1 mutations result in a common frameshifted sequence that generates peptides presented by several class I human leukocyte antigens (HLAs), such as HLA-A*11:01. In this study, we vaccinated HLA-A*11:01-transgenic mice with the mtNPM1 peptide AVEEVSLRK and isolated six functional TCRs from mtNPM1-reactive lymphocytes. When engineered into human T cells, two of these TCRs consistently mediated robust and specific lysis of an AML cell line and primary AML cells co-expressing HLA-A*11:01 and mtNPM1. Neither TCR recognized related human peptides, HLA-A*11:01-expressing normal peripheral blood mononuclear cells or stem/progenitor cells, or cells expressing diverse allogeneic HLAs, suggesting a low risk of cross-reactivity and alloreactivity. In an AML xenograft model, both TCRs controlled AML in hematopoietic organs, although extramedullary tumors emerged during treatment, potentially reflecting the aggressive behavior of the model that may not be representative of AML in patients. Together, these data suggest that the two TCRs represent strong candidates for further preclinical development in adoptive T cell therapy for NPM1-mutated, HLA-A*11:01-positive AML. These results also support the use of HLA-transgenic mice as a platform for generating TCRs targeting oncogene-derived epitopes in hematologic malignancies.

immunology↗

bioRxiv2022

Calcium-activated big conductance (BK) potassium channels traffic through nuclear envelopes into kinocilia in skate electrosensory cells

Electroreception through ampullae of Lorenzini in the little skate, Leucoraja erinacea, involves functional coupling between voltage-activated calcium channels (CaV1.3, cacna1d) and calcium-activated big conductance potassium (BK) channels (BK, kcnma1). Whole mount confocal microscopy was used to characterize expression of BK and CaV1.3 in intact ampullae. BK and CaV1.3 are present in electrosensory cell plasma membranes and colocalize with lamin B1 in nuclear envelopes and kinocilia. Predicted nuclear localization signals (NLS) were identified in BK and CaV1.3 by bioinformatic sequence analyses. The BK NLS is bipartite, occurs at an alternative splice site for the mammalian STREX exon and is modified by post-translational phosphorylation. Nuclear localization of skate BK channels was characterized in heterologously-transfected HEK293 cells. Double point mutations in the bipartite NLS (KR to AA, or SVLS to AVLA) independently attenuated BK channel nuclear localization, illustrating that BK trafficking into nuclei and electrosensory cell kinocilia is regulated through a newly identified bipartite NLS.

neuroscience↗

bioRxiv2021

A novel Toxoplasma IMC sutures-associated protein regulates suture protein targeting and colocalizes with membrane trafficking machinery

The cytoskeleton of Toxoplasma gondii is composed of the inner membrane complex (IMC) and an array of underlying microtubules that provide support at the periphery of the parasite. Specific subregions of the IMC carry out distinct roles in replication, motility, and host cell invasion. Building on our previous in vivo biotinylation (BioID) experiments of the IMC, we identify here a novel protein that localizes to discrete punctae that are embedded in the parasites cytoskeleton along the IMC sutures. Gene knockout analysis shows that loss of the protein results in defects in cytoskeletal suture protein targeting, cytoskeletal integrity, parasite morphology, and host cell invasion. We then use deletion analyses to identify a domain in the N-terminus of the protein that is critical for both localization and function. Finally, we use the protein as bait for in vivo biotinylation which identifies several other proteins that colocalize in similar spot-like patterns. These putative interactors include several proteins that are implicated in membrane trafficking and are also associated with the cytoskeleton. Together, this data reveals an unexpected link between the IMC sutures and membrane trafficking elements of the parasite and suggests that the sutures punctae are likely a portal for trafficking cargo across the IMC.

microbiology↗

bioRxiv2020

Nuclear localization of calcium-activated BK channels in skate ampullary electroreceptors

Ampullae of Lorenzini are sensory organs capable of detecting microvolt gradients in seawater. Electroreception involves interplay between voltage-dependent calcium channels CaV1.3 and big conductance calcium-activated potassium (BK) channels in apical membranes of receptor cells. Expression of BK (kcnma1) and CaV1.3 (cacna1d) channels in skate (Leucoraja erinacea) ampullary electroreceptors was studied by in situ confocal microscopy. BK and CaV1.3 channels colocalize in plasma membranes, ribbon synapses and kinocilia. BK channels additionally colocalize with chromatin and nuclear lamins in electroreceptor cells. Bioinformatic sequence analysis identified an alternatively spliced bipartite nuclear localization sequence (NLS) in kcnma1 (at site of mammalian STREX exon). Skate kcnma1 wild type cDNA transfected into HEK293 cells localized to the endoplasmic reticulum and nucleus. Mutations in the NLS (KR[->]AA or SVLS[->]AVLA) independently attenuated nuclear translocation from endoplasmic reticulum. BK channel localization may be controlled by splicing or phosphorylation to tune electroreception and modulate gene expression.

neuroscience↗

bioRxiv2018

Translation Attenuation by Minocycline Increases Lifespan and Improves Proteostasis in Old Post-Stress-Responsive Organisms

Aging impairs the activation of Stress Signaling Pathways (SSPs), preventing the induction of longevity mechanisms late in life. Here we show that the antibiotic minocycline increases lifespan and reduces protein aggregation even in old, SSP-deficient C. elegans by targeting cytoplasmic ribosomes, preferentially attenuating translation of highly translated mRNAs. In contrast to most other longevity paradigms, minocycline inhibits rather than activates all major SSPs and extends lifespan in mutants deficient in the activation of SSPs, lysosomal or autophagic pathways. We propose that minocycline lowers the concentration of newly synthesized aggregation-prone proteins, resulting in a relative increase in protein-folding capacity without the necessity to induce protein-folding pathways. Our study suggests that in old individuals with incapacitated SSPs or autophagic pathways, pharmacological attenuation of cytoplasmic translation is a promising strategy to reduce protein aggregation. Altogether, it provides a geroprotecive mechanism for the many beneficial effects of tetracyclines in models of neurodegenerative disease.

physiology↗