CRISPR-Cas9-mediated knockout of SPRY2 in human hepatocytes leads to increased glucose uptake and lipid droplet accumulation

A regulatory element associated to NAFLD in the promoter of DIO1 controls LDL-C, HDL-C and triglycerides in hepatic cells

BACKGROUND

Genome-wide association studies (GWAS) have identified genetic variants linked to fat metabolism and related traits, but rarely pinpoint causative variants. This limitation arises from GWAS not considering functional implications of noncoding variants that can affect transcription factor binding and potentially regulate gene expression. The aim of this study is to investigate a candidate noncoding functional variant within a genetic locus flagged by a GWAS SNP associated with non-alcoholic fatty liver disease (NAFLD), a condition characterized by liver fat accumulation in non-alcohol consumers.

METHODS

CRISPR-Cas9 gene editing in HepG2 cells was used to modify the regulatory element containing the candidate functional variant linked to NAFLD. Global gene expression in mutant cells was assessed through RT-qPCR and targeted transcriptomics. A phenotypic assay measured lipid droplet accumulation in the CRISPR-Cas9 mutants.

RESULTS

The candidate functional variant, rs2294510, closely linked to the NAFLD-associated GWAS SNP rs11206226, resided in a regulatory element within the DIO1 gene's promoter region. Altering this element resulted in changes in transcription factor binding sites and differential expression of candidate target genes like DIO1, TMEM59, DHCR24, and LDLRAD1, potentially influencing the NAFLD phenotype. Mutant HepG2 cells exhibited increased lipid accumulation, a hallmark of NAFLD, along with reduced LDL-C, HDL-C and elevated triglycerides.

CONCLUSIONS

This comprehensive approach, that combines genome editing, transcriptomics, and phenotypic assays identified the DIO1 promoter region as a potential enhancer. Its activity could regulate multiple genes involved in the NAFLD phenotype or contribute to defining a polygenic risk score for enhanced risk assessment in NAFLD patients.

Genetic advancements in obesity management and CRISPR-Cas9-based gene editing system

Human genome research has reached new heights in the recent decade thanks to a major advance in genome editing. Genome editing enables scientists to understand better the functions of a single gene and its impact on a wide range of diseases. In brief, genome editing is a technique for introducing alterations into specific DNA sequences, such as insertions, deletions, or base substitutions. Several methods are adopted to perform genome editing and clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated nuclease 9 (Cas9) systems. Unfortunately, despite substantial progress in understanding the molecular pathways behind obesity, anti-obesity medications are now ineffective. If you are obese, a 10% weight decrease would be preferable to healthy body weight for most people. CRISPR-Cas9, on the other hand, has been shown to reduce body weight by an astonishing 20%. Hence, this updated review elaborates on the molecular basis of obesity, risk factors, types of gene therapy, possible mechanisms, and advantages of the CRISPR-Cas9 system over other methods.

Potential underlying genetic associations between keratoconus and diabetes mellitus

Background Keratoconus (KC) is the most common ectatic corneal disease, characterized by significantly localized thinning of the corneal stroma. Genetic, environmental, hormonal, and metabolic factors contribute to the pathogenesis of KC. Additionally, multiple comorbidities, such as diabetes mellitus, may affect the risk of KC. Main Body Patients with diabetes mellitus (DM) have been reported to have lower risk of developing KC by way of increased endogenous collagen crosslinking in response to chronic hyperglycemia. However, this remains a debated topic as other studies have suggested either a positive association or no association between DM and KC. To gain further insight into the underlying genetic components of these two diseases, we reviewed candidate genes associated with KC and central corneal thickness in the literature. We then explored how these genes may be regulated similarly or differentially under hyperglycemic conditions and the role they play in the systemic complications associated with DM. Conclusion Our comprehensive review of potential genetic factors underlying KC and DM provides a direction for future studies to further determine the genetic etiology of KC and how it is influenced by systemic diseases such as diabetes.

Differential and spatial expression meta-analysis of genes identified in genome-wide association studies of depression

Major depressive disorder (MDD) is the most prevalent psychiatric disorder worldwide and affects individuals of all ages. It causes significant psychosocial impairments and is a major cause of disability. A recent consortium study identified 102 genetic variants and 269 genes associated with depression. To provide targets for future depression research, we prioritized these recently identified genes using expression data. We examined the differential expression of these genes in three studies that profiled gene expression of MDD cases and controls across multiple brain regions. In addition, we integrated anatomical expression information to determine which brain regions and transcriptomic cell types highly express the candidate genes. We highlight 12 of the 269 genes with the most consistent differential expression: MANEA, UBE2M, CKB, ITPR3, SPRY2, SAMD5, TMEM106B, ZC3H7B, LST1, ASXL3, ZNF184 and HSPA1A. The majority of these top genes were found to have sex-specific differential expression. We place greater emphasis on ZNF184 as it is the top gene in a more conservative analysis of the 269. Specifically, the differential expression of ZNF184 was strongest in subcortical regions in males and females. Anatomically, our results suggest the importance of the dorsal lateral geniculate nucleus, cholinergic, monoaminergic and enteric neurons. These findings provide a guide for targeted experiments to advance our understanding of the genetic underpinnings of depression.

Harnessing the potential of CRISPR-based platforms to advance the field of hospital medicine

INTRODUCTION

Clustered regularly interspaced short palindromic repeats (CRISPR) are segments of nucleic acid that play a role in prokaryotic defense and form the basis of a genome editing technology that allows permanent alteration of genetic material. This methodology, known as CRISPR-Cas9, is poised to revolutionize molecular biology, but no literature yet exists on how these advances will affect hospitalists.

AREAS COVERED

These specialists in inpatient medicine care for a wide variety of hospitalized patients, including those with infectious disease, cancer, cardiovascular disease, autoimmune disease, hematologic disease, and a variety of other conditions that may soon be impacted by advances in gene-modifying technology provided by CRISPR-Cas9. A Literature search was performed using PubMed [1 December 2019-17 April 2020].

EXPERT OPINION

This paper reviews the remarkable diagnostic and therapeutic potential of the CRISPR-Cas9 platform and concludes with a look at ethical issues and technical hurdles pertaining to the implementation of permanent gene modification in the practice of Hospital Medicine.