Investigating the potential impact of PCSK9-inhibitors on mood disorders using eQTL-based Mendelian randomization

Association of GLP1R locus with mental ill-health endophenotypes and cardiometabolic traits: A trans-ancestry study in UK Biobank

AIMS

Glucagon-like peptide 1 receptor agonists (GLP1RA), used to treat type 2 diabetes and obesity, have been associated with off-target behavioural effects. We systematically assessed genetic variation in the GLP1R locus for impact on mental ill-health (MIH) and cardiometabolic phenotypes across diverse populations within UK Biobank.

MATERIALS AND METHODS

All genetic variants with minor allele frequency >1% in the GLP1R locus were investigated for associations with MIH phenotypes and cardiometabolic phenotypes. Linear or Logistic regression analyses (adjusted for age, sex, population structure and genotyping chip) were conducted separately in unrelated individuals of self-reported white British (N = 408 774), white European (N = 50 314), South Asian (N = 7667), multiple-ancestry groups (N = 10 437) or African-Caribbean (N = 7641) subsets. All ancestries were subsequently combined in an inverse variance-weighted fixed effects meta-analysis. Bonferroni correction for multiple testing was applied (for number of independent genetic variants).

RESULTS

Associations were identified between GLP1R variants and body mass index (BMI), blood pressure and type 2 diabetes in all ancestries. All ancestries except South Asian had significant MIH associations (mood instability: rs111265626-G, odds ratio [OR] 0.851 [confidence interval, CI 0.79-0.92], risk-taking behaviour: rs75408972-T, OR 1.05 [CI 1.03-1.08] or chronic pain: rs9296280-C, OR 0.645 [CI 0.54-0.78]). The trans-ancestry meta-analysis showed mainly consistent effect sizes and directions for metabolic traits, but discordant directions MIH associations. Only signals for chronic pain, stroke and BMI influenced expression of GLP1R.

CONCLUSIONS

GLP1R variants have consistent cardiometabolic effects across ancestries, but effects on MIH phenotypes are more varied. Any observed behavioural changes with GLP1RA are likely not acting directly through GLP1R.

Reducing LDL-Cholesterol to Very Low Levels: Sailing Between Established Benefits and Potential Risks

In view of the growing evidence supporting more marked reductions of low-density lipoprotein cholesterol (LDL-C), according to the concept of "the lower is better" and with the availability of powerful and well tolerated lipid-lowering drugs, physicians are facing today with the clinical management of patients with very low LDL-C levels. The fear of potential risks linked to extreme reductions of LDL-C down to very low levels may lead to the de-escalation of treatments with consequent paradoxical unfavorable consequences due to the exposure to a higher cardiovascular risk. The aim of this review is to point out evidence of very low LDL-C clinical impact, with a focus on potential adverse effects. Research on cholesterol homeostasis has identified complex mechanisms which guarantee cell functions even when circulating cholesterol levels are very low. The almost complete self-sufficiency of the human body in terms of cholesterol needs is confirmed by evidence derived from genetically determined models with very low LDL-C levels. Studies on the potential harm of lowering LDL-C to very low concentrations do not confirm an increased risk of cancer or neurodegenerative disease attributable to lipid-lowering treatments, whereas evidence suggests a potential benefit in these settings. A potential increased risk of hemorrhagic stroke has been reported, suggesting tight monitoring and control of blood pressure should be implemented in patients with very low LDL-C levels. With regard to statin treatment, a dose-dependent increased risk of newly diagnosed diabetes has been reported. This adverse effect has not been found with more recently approved lipid-lowering drugs.

Targeting RAC1 might be a potential therapeutic strategy for diabetic kidney disease: a Mendelian randomization study

PURPOSE

This study aimed to ascertain the causal association between Ras-related C3 botulinum toxin substrate 1 (RAC1) and the incidence and progression of diabetic kidney disease (DKD) through Mendelian randomization analysis.

METHODS

RAC1 expression, evaluated using expression quantitative trait loci data from the eQTLGen Consortium, was served as the exposure variable. Outcomes encompassed the risk of DKD, end-stage renal disease (ESRD), albuminuria assessed by the urinary albumin-to-creatinine ratio (ACR), and estimated glomerular filtration rate (eGFR) among individuals with diabetes. Causal associations were computed using the inverse variance weighted (IVW), weighted median, and MR-PRESSO models. Additionally, we conducted analyses for heterogeneity, horizontal pleiotropy, and sensitivity.

RESULTS

This study revealed a causal association between the genetic activation of RAC1 and an elevated risk of DKD among individuals with diabetes [IVW, odds ratio (OR) = 1.28, 95% confidence intervals (CI) 1.08-1.51, P = 0.004]. Furthermore, increased expression of RAC1 was linked to a higher risk of ESRD (IVW, OR = 1.20, 95% CI 1.02-1.43, P = 0.032). Excessive RAC1 expression was causally associated with elevated ACR (IVW, β = 0.052, 95% CI 0.003-0.100, P = 0.036). However, the analysis regarding RAC1 and eGFR showed significant heterogeneity and pleiotropy, with no discernible causal relationship.

CONCLUSIONS

These findings suggested a positive correlation between the genetic activation of RAC1 and the incidence of DKD, the risk of ESRD, and exacerbated albuminuria among individuals with diabetes. Targeting RAC1 might potentially serve as a therapeutic strategy for DKD.

The role and advance of ubiquitination and deubiquitination in depression pathogenesis and treatment

Depression is a common neuropsychiatric disease that is characterized by long-term, repeated low mood, pain and despair, pessimism, and even suicidal tendencies. Increasing evidence has shown that ubiquitination and deubiquitination are closely related to the occurrence of depression, including pathological morphogenesis, neuroplasticity, synaptic transmission, neuroinflammation, and so forth. The development of depression is regulated by intracellular proteins that undergo various posttranslational modifications, including ubiquitination, which falls under the epigenetics category. Although there have been studies and reviews of literature on epigenetics and depression, a systematic review of ubiquitination modification and depression has not been reported. In addition, with the deepening of research on depression and ubiquitination, the development of drugs targeting the ubiquitin system has gradually increased, but it is still not mature, so there is an urgent need to find new antidepressant drug targets. E3 ubiquitin ligases and deubiquitinating enzymes can regulate the occurrence and development of depression in a variety of ways, which may be a direction for the treatment of depression in the future. Therefore, this review describes the latest progress of ubiquitination and deubiquitination in the regulation of depression, summarizes the published signal pathways of ubiquitination and deubiquitination involved in depression, emphasizes the targets and mechanisms of E3 ubiquitin ligases and deubiquitinase in the regulation of depression, and further discusses the therapeutic targets of targeting ubiquitination modification systems to regulate depression.

Investigating the association of the effect of genetically proxied PCSK9i with mood disorders using cis-pQTLs: A drug-target Mendelian randomization study

PCSK9-inhibitors (PCSK9i) are new drugs recently approved to lower LDL-cholesterol levels. However, due to the lack of long-term clinical data, the potential adverse effects of long-term use are still unknown. The PCSK9 genetic locus has been recently implicated in mood disorders and hence we wanted to assess if the effect of PCSK9i that block the PCSK9 protein can lead to an increase in the incidence of mood disorders. We used genetically-reduced PCSK9 protein levels (pQTLs) in plasma, serum, cerebrospinal fluid as a proxy for the effect of PCSK9i. We performed Mendelian randomization analyses using PCSK9 levels as exposure and mood disorder traits major depressive disorder, mood instability, and neuroticism score as outcomes. We find no association of PCSK9 levels with mood disorder traits in serum, plasma, and cerebrospinal fluid. We can conclude that genetically proxied on-target effect of pharmacological PCSK9 inhibition is unlikely to contribute to mood disorders.

Function of proprotein convertase subtilisin/kexin type 9 and its role in central nervous system diseases: An update on clinical evidence

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has attracted lots of attention in preventing the clearance of plasma low-density lipoprotein cholesterol (LDL-C). PCSK9 inhibitors are developed to primarily reduce the cardiovascular risk by lowering LDL-C level. Recently, a number of pleiotropic extrahepatic functions of PCSK9 beyond the regulation of cholesterol metabolism, particularly its effects on central nervous system (CNS) diseases have been increasingly identified. Emerging clinical evidence have revealed that PCSK9 may play a significant role in neurocognition, depression, Alzheimer's disease, and stroke. The focus of this review is to elucidate the functions of PCSK9 and highlight the effects of PCSK9 in CNS diseases, with the aim of identifying the potential risks that may arise from low PCSK9 level (variant or inhibitor) in the clinical practice.

Role of PCSK9 inhibition during the inflammatory stage of SARS-COV-2: an updated review

The potential role of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition in the management of COVID-19 and other medical conditions has emerged as an intriguing area of research. PCSK9 is primarily known for its impact on cholesterol metabolism, but recent studies have unveiled its involvement in various physiological processes, including inflammation, immune regulation, and thrombosis. In this abstract, the authors review the rationale and potential implications of PCSK9 inhibition during the inflammatory stage of SARS-CoV-2 infection. Severe cases of COVID-19 are characterized by an uncontrolled inflammatory response, often referred to as the cytokine storm, which can lead to widespread tissue damage and organ failure. Preclinical studies suggest that PCSK9 inhibition could dampen this inflammatory cascade by reducing the production of pro-inflammatory cytokines. Additionally, PCSK9 inhibition may protect against acute respiratory distress syndrome (ARDS) through its effects on lung injury and inflammation. COVID-19 has been linked to an increased risk of cardiovascular complications, especially in patients with pre-existing cardiovascular conditions or dyslipidemia. PCSK9 inhibitors are known for their ability to lower low-density lipoprotein (LDL) cholesterol levels by enhancing the recycling of LDL receptors in the liver. By reducing LDL cholesterol, PCSK9 inhibition might protect blood vessels from further damage and lower the risk of atherosclerotic plaque formation. Moreover, PCSK9 inhibitors have shown potential antithrombotic effects in preclinical studies, making them a potential avenue to mitigate the increased risk of coagulation disorders and thrombotic events observed in COVID-19. While the potential implications of PCSK9 inhibition are promising, safety considerations and possible risks need careful evaluation. Hypocholesterolemia, drug interactions, and long-term safety are some of the key concerns that should be addressed. Clinical trials are needed to establish the efficacy and safety of PCSK9 inhibitors in COVID-19 patients and to determine the optimal timing and dosing for treatment. Future research opportunities encompass investigating the immune response, evaluating long-term safety, exploring combination therapy possibilities, and advancing personalized medicine approaches. Collaborative efforts from researchers, clinicians, and policymakers are essential to fully harness the therapeutic potential of PCSK9 inhibition and translate these findings into meaningful clinical outcomes.