Biology subjects

Medishetti, R.

Publications and source records attributed to Medishetti, R..

3 recordsLinked to original sources

bioRxiv2025

GPCR-targeted imaging and manipulation of homeostatic microglia in living systems

Microglia, the resident innate immune cells of the brain, are known to perform key roles such as synaptic pruning, apoptotic debris removal, and pathogen defense in the central nervous system. Microglial mutations are directly linked to many neurodevelopmental (e.g., schizophrenia) and neurodegenerative (e.g., Alzheimers disease) disorders, indicating the diagnostic and therapeutic potential of microglia for treating these conditions. Currently, we lack robust molecular tools to specifically image and manipulate microglia in vivo, which presents a major hurdle in our understanding of the brain-wide functions of these cells during the early onset of brain diseases. Here, we describe a molecular technology for imaging and manipulation of homeostatic microglia in live organisms (e.g., in zebrafish and mice) by covalently targeting the purinergic receptor, P2RY12. Using this technology, we imaged microglia-pathogen interactions in the larval zebrafish brain and revealed various morphological states of microglia in the adult mouse brain. We further expanded the microglia labelling approach to single-microglia tracking and microglial surfaceome mapping using photoactivatable fluorophores and photoproximity labelling, respectively. We anticipate the use of this universal tool for studying microglial biology across species to reveal the dynamics and polarization of resting microglia into a reactive state found in many neurodegenerative diseases.

immunology↗

bioRxiv2025

LEVERAGING TRANSFER LEARNING FOR HIGH-ACCURACY PHENOTYPIC SCREENING IN ZEBRAFISH IMAGE ANALYSIS

This paper presents a method for classifying zebrafish images captured before and after drug administration. Leveraging the power of transfer learning and fine-tuning, the approach effectively overcomes the challenges of limited datasets in biomedical imaging. By employing a pre-trained convolutional neural network (CNN) as the base model, transfer learning allows us to utilize learned features from large-scale image datasets, significantly reducing training time and computational resources. Fine-tuning specific layers of the model on our zebrafish dataset further enhances its ability to detect subtle visual differences induced by drug administration. The proposed approach achieves high accuracy in classifying zebrafish images, demonstrating its potential as a reliable tool for analysing phenotypic changes due to pharmacological interventions. This model could be instrumental in accelerating drug discovery and research in zebrafish-based assays, offering a scalable and efficient solution for image-based biomedical analysis.

bioinformatics↗

bioRxiv2024

Impaired ovarian development in a zebrafish fmr1 knockout model

Fragile X syndrome (FXS) is an inherited neurodevelopmental disorder and the leading genetic cause of autism spectrum disorders. FXS is caused by loss of function mutations in Fragile X mental retardation protein (FMRP), an RNA binding protein that is known to regulate translation of its target mRNAs, predominantly in the brain and gonads. The molecular mechanisms connecting FMRP function to neurodevelopmental phenotypes are well understood. However, neither the full extent of reproductive phenotypes, nor the underlying molecular mechanisms have been as yet determined. Here, we developed new fmr1 knockout zebrafish lines and show that they mimic key aspects of FXS neuronal phenotypes across both larval and adult stages. Results from the fmr1 knockout females also showed that altered gene expression in the brain, via the neuroendocrine pathway contribute to distinct abnormal phenotypes during ovarian development and oocyte maturation. We identified at least three mechanisms underpinning these defects, including altered neuroendocrine signaling in sexually mature females resulting in accelerated ovarian development, altered expression of germ cell and meiosis promoting genes at various stages during oocyte maturation, and finally a strong mitochondrial impairment in late stage oocytes from knockout females. Our findings have implications beyond FXS in the study of reproductive function and female infertility. Dissection of the translation control pathways during ovarian development using models like the knockout lines reported here may reveal novel approaches and targets for fertility treatments. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/579749v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@15ea8b3org.highwire.dtl.DTLVardef@195838corg.highwire.dtl.DTLVardef@ef8940org.highwire.dtl.DTLVardef@1bd58a_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG

molecular biology↗