Biology subjects

Balabanov, S.

Publications and source records attributed to Balabanov, S..

3 recordsLinked to original sources

bioRxiv2023

Viscoelastic Deformability Cytometry: Ultra-high Throughput Platform for Mechanical Phenotyping of Cells in Liquid and Solid Biopsies

Due to the differences in mechanical properties between cancer cells and their benign counterparts, the mechanical characteristics of cells have emerged as a significant feature in diagnosing cancer. Consequently, measuring cell deformability as a means of mechanical phenotyping is promising for both the detection and classification of the disease. However, performing high-throughput single-cell deformability measurements on liquid or solid tissue biopsies remains a significant challenge within a clinical setting. Herein, we introduce an ultra-high throughput viscoelastic-based microfluidic platform to measure the cell mechanical properties at rates of up to 100,000 cells/s. Thanks to the viscoelastic property of the fluid, cells are focused and deformed within the same platform obviating the need for any sheath fluid. We used the presented platform for cell phenotyping in both liquid and solid tumor biopsies, such as identification of malignant lymphocytes in peripheral blood samples and glioblastoma-type cell classification from solid tumor samples. The presented platform has the potential to open new opportunities in the assessment of cancer, enable precise mechanical profiling of rare cells, and facilitate sensitive diagnostic applications.

bioengineering↗

bioRxiv2020

Polyamine Metabolism Regulates the T Cell Epigenome Through Hypusination

We report here a central role for polyamines in T cell differentiation and function. Deficiency in ornithine decarboxylase (ODC), a critical enzyme for polyamine synthesis, resulted in a profound failure of CD4+ T cells to adopt correct subset specification, underscored by ectopic expression of multiple cytokines and lineage-defining transcription factors across TH1, TH2, TH17, and Treg polarizing conditions, and enhanced colitogenic potential. T cells deficient in deoxyhypusine synthase (DHPS) or deoxyhypusine hydroxylase (DOHH), which sequentially utilize polyamines to generate hypusine, phenocopied Odc-deficient T cells, and mice in which T cells lacked Dhps or Dohh developed colitis. Polyamine-hypusine pathway enzyme deficiency caused widespread chromatin and transcriptional dysregulation accompanied by alterations in histone methylation, histone acetylation, and TCA cycle metabolites. Epigenetic modulation by 2-hydroxyglutarate, or histone acetyltransferase inhibition, restored CD4+ T cell subset specification. Thus, polyamine synthesis via hypusine is critical for maintaining the epigenome to focus TH cell subset fidelity.

immunology↗

bioRxiv2018

Translational control of TFEB and autophagy via eIF5A rejuvenates B cell immunity

Failure to make adaptive immune responses is a hallmark of aging. In particular reduced B cell function leads to poor vaccination efficacy and a high prevalence of infections in the elderly. However, the molecular mechanism underlying immune senescence is largely unknown. Here we show that autophagy levels are specifically reduced in mature lymphoid cells, leading to compromised memory B cell responses in old individuals. Spermidine, a naturally occurring polyamine metabolite, induces autophagy in vivo and rejuvenates memory B cell responses in an autophagy-dependent manner. Mechanistically, spermidine post-translationally modifies the translation factor eIF5A, which assists the synthesis of TFEB, a key transcription factor of autophagy. Spermidine is depleted in the elderly, leading to reduced TFEB expression and autophagy. Replenishing spermidine restored this pathway and improved the responses of old human B cells. Taken together, our results reveal an unexpected autophagy regulatory mechanism mediated by eIF5A at the translational level, and this pathway can be harnessed to rejuvenate immune senescence in humans.

cell biology↗