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Biology subjects

Bhattacharya, S. K.

Publications and source records attributed to Bhattacharya, S. K..

5 recordsLinked to original sources

Multiomic analysis of non-glaucomatous human trabecular meshwork cells.

Glaucoma is an irreversible blinding disease that affects millions of individuals worldwide. Elevated intraocular pressure (IOP), regulated by the trabecular meshwork (TM) in the anterior eye, is the only modifiable risk factor. Human TM cells can be cultured from donor eyes, providing a precious resource for studying factors that induce or prevent glaucoma. The goal of this study was to produce datasets that define the molecular profile of human non-glaucomatous TM cells. Using 18 human TM cell strains cultured from non-glaucomatous individuals deposited from seven laboratories in the USA and UK, this study used transcriptomic, proteomic, lipidomic, and metabolomic analyses to characterize the molecular content of TM cells. The data herein provides the most comprehensive multiomic analyses of human TM cells to date and will be a useful resource for researchers and clinicians in the TM and glaucoma fields.

cell biology↗

Coil and flow diverting stents as drug delivery platforms for cerebral aneurysm treatment

Cerebral aneurysm occlusion with coils and flow diverting stents has become the first line treatment for both unruptured and ruptured cerebral aneurysms. As these technologies have advanced, there have been changes in device shape and surface coating to enhance aneurysm embolization while reducing stent thrombogenicity. Drug eluting stents have been used with great success in the targeted delivery of rapamycin, a mTOR complex 1 inhibitor to prevent restenosis in coronary and peripheral artery disease. However, few studies have investigated the use of coils and stents as delivery platforms for sustained drug release to cerebral aneurysm tissue. In this study, we used the bio-compatible and degradable polymers, gelatin and PLGA and a simple evaporative coating technique to investigate the release of rapamycin over time from coated platinum coils and Pipeline flow diverting stents. Rapamycin coated coils were incubated with human vascular endothelial cells in vitro to confirm therapeutic levels of rapamycin release. The rate of rapamycin release was similar in both gelatin and PLGA coated coils and was sustained for more than three weeks. Rapamycin was bioactive, at a therapeutic dose and inhibited mTOR complex 1 in human brain endothelial cells treated with a rapamycin coated coil. The relative degree of mTOR complex 1 inhibition was greater in PLGA compared to gelatin coated coils. Coating flow diverting stents with a rapamycin-PLGA coating demonstrated continuous rapamycin release over a 35 day period. Reducing the percent PLGA polymer concentration caused a robust and sustainable release of rapamycin. The PLGA coating was resilient enough to allow device recapturing without affecting rapamycin eluting rates or device deployment and expansion. This work provides a simple, feasible and tunable method to coat occlusion devices for preclinical studies investigating targeted drug delivery for improved parent vessel healing and aneurysm obliteration.

bioengineering↗

Cerebral vascular tortuosity and aneurysm formation and rupture: a novel vessel tortuosity scale

Cerebral aneurysm (CA) rupture is the most common cause of nontraumatic subarachnoid hemorrhage. Recent data suggests that tortuosity is associated with aneurysm formation and rupture risk. We aimed to determine if tortuosity correlates with CA development and rupture in a mouse CA model and to develop a novel tortuosity scale to be used for in vivo CA studies. A highly validated, elastase-mouse CA model was used to assess cerebral vessel tortuosity with CA formation and rupture in sham and elastase groups. A 4-point ordinal scale was created to evaluate predictive capacity for vessel tortuosity level and CA formation and rupture. Nearly all sham animals (92%) had little to no vessel tortuosity on the visual scale (median, IQR: 1, [1-2]), compared to 24% in the elastase groups (2, [2-3]) (p=0.001). Sham cohorts had zero animals with highly tortuous vessels, while 3.5mU and 35mU cohorts had >35% of animals with significant visual tortuosity, p=0.003 and p<0.000, respectively. CA formation and rupture was higher in the elastase groups compared to the sham group (p=0.002). Both the visual scale and tortuosity index significantly predicted CA formation (p<0.001) and rupture (p<0.001). A novel tortuosity scale is highly predictive of CA formation and rupture in vivo. It may offer a new measurement to better understand vessel stress in the pathogenesis and progression of CAs.

neuroscience↗

Development of an efficient single-cell cloning and expansion strategy for genome edited induced pluripotent stem cells

Disease-specific human induced pluripotent stem cells (hiPSCs) can be generated directly from individuals with known disease characteristics or alternatively be modified using genome editing approaches to introduce disease causing genetic mutations to study the biological response of those mutations. The genome editing procedure in hiPSCs is still inefficient, particularly when it comes to homology directed repair (HDR) of genetic mutations or targeted transgene insertion in the genome and single cell cloning of edited cells. In addition, genome editing processes also involve additional cellular stresses such as trouble with cell viability and genetic stability of hiPSCs. Therefore, efficient workflows are desired to increase genome editing application to hiPSC disease models and therapeutic applications. Apart from genome editing efficiency, hiPSC survival following single-cell cloning has proved to be challenging and has thus restricted the capability to easily isolate homogeneous clones from edited hiPSCs. To this end, we demonstrate an efficient workflow for feeder-free single cell clone generation and expansion in both CRISPR-mediated knock-out (KO) and knock-in (KI) hiPSC lines. Using StemFlex medium and CloneR supplement in conjunction with Matrigel cell culture matrix, we show that cell viability and expansion during single-cell cloning in edited and unedited cells is significantly enhanced. Our reliable single-cell cloning and expansion workflow did not affect the biology of the hiPSCs as the cells retained their growth and morphology, expression of various pluripotency markers and normal karyotype. This simplified and efficient workflow will allow for a new level of sophistication in generating hiPSC-based disease models to promote rapid advancement in basic research and also the development of novel cellular therapeutics.

cell biology↗

Hypoxia driven oncometabolite L-2HG maintains "stemness"-differentiation balance and facilitates immune suppression in pancreatic cancer

2-hydroxyglutarate (2-HG) has gained considerable importance in glioma and blood cancers that have mutations in the IDH1/2 gene. In the current study we show for the first time that pancreatic tumors produce 2HG in the absence of IDH1/2 mutation. Our study shows that hypoxic pancreatic tumors that have activated lactate dehydrogenase (LDH) activity, produce the L-isoform of 2HG. Metabolic mass spectrometric analysis along with chiral derivatization showed that pancreatic cancer cells as well as stromal cells secrete the L-isomeric form of 2-hydroxyglutarate (L-2HG) when exposed to hypoxic environment. Serum analysis of human pancreatic cancer patients also showed similar accumulation of L-2HG. Our results showed that this abnormally accumulated L-2HG regulates self-renewal by increasing expression of genes associated with stemness (Sox-2, CD133) and by decreasing expression of differentiation genes (Pdx-1, HB9, NKX6.1). Further analysis showed that secreted L-2HG mediates cross talk with immune T-cells and hampers their proliferation and migration thereby suppressing the anti-tumor immunity. In vivo targeting of LDH enzyme with inhibitor (GSK2837808A) showed decrease in L-2HG as well as subsequent tumor regression and sensitization to immune-checkpoint therapy. Present study shows for the first time that hypoxia mediated accumulation of L-2HG drives self-renewal in pancreatic cancer by shifting critical balance of gene expression towards stemness and promotes immune suppression by impairing T cell activation in this disease. Additionally, it indicates that targeting LDH can sensitize pancreatic tumors to anti-PD1 therapy by decreasing L-2HG and reverting their immune evasive function.

cancer biology↗