Biology subjects

Pai, A.

Publications and source records attributed to Pai, A..

3 recordsLinked to original sources

bioRxiv2022

Semi-automated protocol to quantify and characterize fluorescent, 3D vascular images

The microvasculature facilitates gas exchange, provides nutrients to cells, and regulates blood flow in response to stimuli. Vascular abnormalities are an indicator of pathology for various conditions, such as compromised vessel integrity in small vessel disease and angiogenesis in tumors. Traditional immunohistochemistry enables visualization of tissue cross-sections containing exogenously labeled vasculature. Although this approach can be utilized to quantify vascular changes within small fields-of-view, it is not a practical way to study the vasculature on the scale of whole organs. Three-dimensional (3D) imaging presents a more appropriate method to visualize the vascular architecture in tissue. Here we describe the complete protocol that we use to characterize the vasculature of different organs in mice encompassing the methods to fluorescently label vessels, optically clear tissue, collect 3D vascular images, and quantify these vascular images with a semi-automated approach. To validate the automated segmentation of vascular images, one user manually segmented fifty random regions of interest across different vascular images. The automated segmentation results had an average sensitivity of 80{+/-}8% and an average specificity of 90{+/-}5% when compared to manual segmentation. Applying this procedure of image analysis presents a method to reliably quantify and characterize vascular networks in a timely fashion. This procedure is also applicable to other methods of tissue clearing and vascular labels that generate 3D images of microvasculature.

bioengineering↗

bioRxiv2021

A cohesin traffic pattern genetically linked to gene regulation

Cohesin-mediated loop extrusion folds interphase chromosomes at the ten to hundreds kilobases scale. This process produces structural features such as loops and topologically associating domains. We identify three types of cis-elements that define the chromatin folding landscape generated by loop extrusion. First, CTCF sites form boundaries by stalling extruding cohesin, as shown before. Second, transcription termination sites form boundaries by acting as cohesin unloading sites. RNA polymerase II contributes to boundary formation at transcription termination sites. Third, transcription start sites form boundaries that are mostly independent of cohesin, but are sites where cohesin can pause. Together with cohesin loading at enhancers, and possibly other cis-elements, these loci create a dynamic pattern of cohesin traffic along the genome that guides enhancer-promoter interactions. Disturbing this traffic pattern, by removing CTCF barriers, renders cells sensitive to knock-out of genes involved in transcription initiation, such as the SAGA and TFIID complexes, and RNA processing such DEAD-Box RNA helicases. In the absence of CTCF, several of these factors fail to be efficiently recruited to active promoters. We propose that the complex pattern of cohesin movement along chromatin contributes to appropriate promoter-enhancer interactions and localization of transcription and RNA processing factors to active genes. HIGHLIGHTSO_LIAt least three types of chromatin boundaries regulate a cohesin traffic pattern. C_LIO_LIThe cohesin traffic pattern guides enhancer-promoter interactions. C_LIO_LIRemoving CTCF renders cells sensitive to deletion of RNA processing and gene regulation genes. C_LIO_LIDepleting CTCF affects localization of RNA processing and gene regulatory proteins. C_LI

genomics↗

bioRxiv2021

Sesamol and its derivative investigated as antiandrogen - A potential prevention to prostate cancer in rats

Androgen signaling is essential for the development of prostate cancer (PCa) initiated from prostatic basal cells with collocation of androgen receptor gene mutations. Phytoestrogens, the naturally occurring compounds are AR antagonist. These compounds downregulate prostate-specific antigen (PSA) expression and cell proliferation. Thus, this gives a track to research these compounds as a possible treatment for PCa. In this work, STITCH and molecular docking predict the conformation of ligands inside the suitable target binding site. Therefore, a study was planned to know the interactions among SM and its derivatives with AR. It was further, evaluated for in vitro evaluation on LNCaP, PC-3, and DU-145 using MTT studies. The two lead compounds shortlisted from MTT studies were further analyzed for androgen-regulated genes by using RT-PCR, western blot studies and an animal model of prostate cancer. We found that SM and its derivative (3-MA) may prevent the development of PCa by androgen pathway.

cancer biology↗