Background: Clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein (Cas) systems are the latest addition to the plethora of gene-editing tools. These systems have been repurposed from their natural counterparts by means of both guide RNA and Cas nuclease engineering. These RNA-guided systems offer greater programmability and multiplexing capacity than previous generation gene editing tools based on zinc finger nucleases and transcription activator like effector nucleases. CRISPR-Cas systems show great promise for individualization of cancer precision medicine. Main body: The biology of Cas nucleases and dead Cas based systems relevant for in vivo gene therapy applications has been discussed. The CRISPR knockout, CRISPR activation and CRISPR interference based genetic screens which offer opportunity to assess functions of thousands of genes in massively parallel assays have been also highlighted. Single and combinatorial gene knockout screens lead to identification of drug targets and synthetic lethal genetic interactions across different cancer phenotypes. There are different viral and non-viral (nanoformulation based) modalities that can carry CRISPR-Cas components to different target organs in vivo. Conclusion: The latest developments in the field in terms of optimization of performance of the CRISPR-Cas elements should fuel greater application of the latter in the realm of precision medicine. Lastly, how the already available knowledge can help in furtherance of use of CRISPR based tools in personalized medicine has been discussed.

Circular RNAs (circRNAs) are a large family of noncoding RNAs that have emerged as novel regulators of gene expression. However, little is known about the function of circRNAs in pancreatic β-cells. Here, transcriptomic analysis of mice pancreatic islet RNA-sequencing data identified 77 differentially expressed circRNAs between mice fed with a normal diet and a high-fat diet. Surprisingly, multiple circRNAs were derived from the intron 2 of the preproinsulin 2 (Ins2) gene and are termed as circular intronic (ci)-Ins2. The expression of ci-Ins2 transcripts in mouse pancreatic islets, and βTC6 cells were confirmed by reverse transcription PCR, DNA sequencing, and RNase R treatment experiments. The level of ci-Ins2 was altered in βTC6 cells upon exposure to elevated levels of palmitate and glucose. Computational analysis predicted the interaction of several RNA-binding proteins with ci-Ins2 and their flanking region, suggesting their role in the ci-Ins2 function or biogenesis. Additionally, bioinformatics analysis predicted the association of several microRNAs with ci-Ins2. Gene ontology and pathway analysis of genes targeted by miRNAs associated with ci-Ins2 suggested the regulation of several key biological processes. Together, our findings indicate that differential expression of circRNAs, especially ci-Ins2 transcripts, may regulate β-cell function and may play a critical role in the development of diabetes.

Systemic PPARγ agonist therapies have been investigated for clinical use in MASLD. Previous studies, however, have shown that PPARγ activation in hepatocytes worsens MASLD. Overall, the precise molecular mechanisms regulated by PPARγ in hepatocyte during MASLD remain incompletely defined. Hepatocyte-specific PPARγ knockout mice were fed a clinically-relevant fast-food diet (FFD) for 2 or 5-months to characterize the role of PPARγ in MASLD progression. PPARγ expression and activity were increased in murine FFD-model and in hepatocytes of human MASLD/MASH patients, based on single-nucleus RNA-sequencing analysis. PPARγ-deletion conferred protection against diet-induced steatosis, fibrosis, and liver injury by suppressing lipogenic, inflammatory, and fibrogenic signaling. Although de-novo fatty-acid synthesis was only modestly affected and compensated with disease progression, enhancement of lipolysis and suppression of lipid droplet stabilization machinery was persistent. PPARγ-deletion robustly inhibited expression and signaling-activity of TGFβ1, a master regulator of hepatic fibrosis, throughout the progression of MASLD. Importantly, a novel PPARγ-HNF4α regulatory axis in MASLD was identified, with increased HNF4α mRNA/protein expression and activation of its downstream metabolic networks in PPARγ-deficient livers. Further, integration of ChIP-seq and transcriptomic analysis revealed that HNF4α might be co-regulating a major fraction (>70%) of genes under direct control of PPARγ during MASLD. This study provides a comprehensive temporal framework for hepatocyte PPARγ function in MASLD, revealing an antagonistic PPARγ-HNF4α transcriptional network that governs hepatic metabolic fate.