LRP6 mutation in a family with early coronary disease and metabolic risk factors

Insights Into Heart-Tumor Interactions in Heart Failure

Heart failure (HF) often coexists with cancer. Beyond the known cardiotoxicity of some cancer treatments, HF itself has been associated with increased cancer incidence. The 2 conditions share common risk factors, mechanisms, and interactions that can worsen patient outcomes. The bidirectional relationship between HF and cancer presents a complex interplay of factors that are not fully understood. Recent preclinical evidence suggests that HF may promote tumor growth via the release of protumorigenic factors from the injured heart, revealing HF as a potentially protumorigenic condition. Our review discusses the biological crosstalk between HF and cancer, emphasizing the impact of HF on tumor growth, with inflammation, and modulating the immune system as central mechanisms. We further explore the clinical implications of this connection and propose future research directions. Understanding the mechanistic overlap and interactions between HF and cancer could lead to new biomarkers and therapies, addressing the growing prevalence of both conditions and enhancing approaches to diagnosis, prevention, and treatment.

Role of Sclerostin in Cardiovascular System

Sclerostin, encoded by the SOST gene, is a novel bone anabolic target for bone diseases. Humanized anti-sclerostin antibody, romosozumab, was approved for treatment of postmenopausal osteoporosis by the US Food and Drug Administration (FDA), but with a black-box warning on cardiovascular risk. The clinical data regarding cardiovascular events from various pre-marketing and post-marketing studies of romosozumab were inconsistent. Overall, the cardiovascular risk of sclerostin inhibition could not be excluded. The restriction of romosozumab in patients with cardiovascular disease history would be necessary. Moreover, genome-wide association study (GWAS) analyses of SOST variants revealed inconsistent results of the association between SOST variations and cardiovascular diseases. Further research incorporating larger sample sizes and functional analyses are necessary. In analyses of serum/tissue sclerostin levels in patients with cardiovascular diseases, the results were controversial but indicated an association between sclerostin and the presence/severity/outcomes of cardiovascular diseases. Nonclinical studies in rodents indicated the inhibitory effect of sclerostin on inflammation, aortic aneurysm, atherosclerosis, and vascular calcification. Sclerostin loop3 participated in the inhibitory effect of sclerostin on bone formation, while the cardiovascular protective effect of sclerostin was independent of sclerostin loop3. Macrophagic sclerostin loop2-apolipoprotein E receptor 2 (ApoER2) interaction participated in the inhibitory effect of sclerostin on inflammation in vitro. Sclerostin in human aortic smooth muscle cells participated in the reduction in calcium deposition. The role of sclerostin in cardiovascular system deserves further investigation.

Lumbar localized fat distribution parameters are independent predictors of osteoporotic vertebral compression re-fractures (OVCRFs) following Percutaneous Kyphoplasty (PKP): a retrospective matched case-control study

OBJECTIVE

To investigate potential risk factors for osteoporotic vertebral compression re-fractures (OVCRFs) following percutaneous kyphoplasty (PKP).

MATERIALS AND METHODS

Patients who underwent PKP from January 2012 to January 2020 were included in this study within the same institution. Cases were defined as patients who experienced OVCRFs, while controls were matched based on corresponding clinical characteristics from those patients without OVCRFs. The lumbar localized fat distribution parameters, including the fat infiltration ratio (FIR) in muscles [multifidus (MF), erector spinae (ES), paravertebral muscles (PVM), and psoas major (PS)] and subcutaneous fat thickness (SFT), were compared between the two groups through radiological data. And other clinical data that may be relevant were also compared. Independent risk factors for OVCRFs after PKP were identified through a binary logistic regression analysis.

RESULT

A total of 1391 patients who underwent PKP were included in this study. 51 patients were categorized into the re-fracture group, and 102 patients were selected as matched controls from the remaining cohort. There were statistically significant differences between the two groups in metrics including MF-FIR, ES-FIR, PVM-FIR, PS-FIR, bone mineral density (BMD), body-mass index (BMI), SFT, hemoglobin (Hb), albumin (ALB), alkaline phosphatase (ALP), and triglycerides (TG) (P < 0.05). Binary logistic regression analysis demonstrated that PVM-FIR (P = 0.003), SFT (P < 0.001), BMD (P = 0.011), and ALP (P = 0.005) were independent predictors for the occurrence of OVCRFs.

CONCLUSION

This study discovered that lumbar localized fat distribution parameters including PVM-FIR and SFT are independent predictors of OVCRFs. Additionally, BMD and ALP were found to be independent predictors of OVCRFs.

Mining of candidate genes related to body size in Chinese native pig breeds based on public data

To study the key genes that influence the body size of local pig breeds in China. Genome-wide SNP chip data from a total of 129 pigs from eight breeds, consisting of four large body size breeds (MZ, HT, ST, RC) and four small body size breeds (XI, BX, WZ, DN) were analyzed. Principal Component Analysis (PCA) was employed to assess the genetic clustering of the eight breeds. Fst and XP-CLR were used to detect selective signals between the large ans small body size breeds groups. The PCA results indicated a clear clustering of small breeds and a dispersion distribution among large breeds. Fst and XP-CLR identified 142 overlapping regions within a 500 kb up & down stream of significant loci. These regions encompassed 520 annotated genes, which were enriched in 34 biological pathways. Gene network analysis highlighted nine key genes, of which five (NPR3, TNFSF11, TBC1D7, FGF2, IGF1R) are known to be associated with bone growth and body size traits in animals. Additionally, four novel candidate genes (IKBKB, SFRP1, LRP6, SPRY1) were identified that might be related to pig body size. Our findings provide a theoretical basis for further revealing the genetic mechanism of pig body size traits.

Structural dynamic investigation of Wnt signalling activation through Co-receptor LRP6

Cancer sparks if the components of the cellular signaling network are aberrantly activated, leading to uncontrolled cell growth and proliferation. One of the most important players of this highly regulated network is the Wnt/β-catenin signaling, with a significant role in human health and disease. The critical co-receptor of this pathway, LRP6, is overexpressed in various cancer types and is a target for therapy. Therefore, understanding the details of the LRP6 structural activation mechanism is of tremendous importance. This research intended to compare the structural-dynamics features of the E3E4 functional domain of LRP6 induced by the activator Wnt3a and the inhibitor, Dkk1_C, compared with the receptor behavior in the apo-state. Using molecular docking, molecular dynamics simulation, and G_MMPBSA calculation, we characterized overlapping binding regions of Wnt3a and Dkk1_C on E3E4. Despite their overall similar interacting regions, Dkk1_C and Wnt induce remarkably different inter-blades hydrogen bonds, structural-dynamics behavior, and conformational energy landscape in E3E4. According to our findings, Dkk1_C stabilized the interaction. between BP3 blades 2-3, 3-4, and 4-5 and BP4 blades 1-6, 1-2, 2-3, and 3-4, aligned with apo-state. However, on the other hand, Wnt distinguishably destabilized the hydrogen bond networks of these blades. Our DCCM analysis also depicted a similar correlation pattern of apo and Dkk1-bound states, and dramatic differences in Wnt-bound state, with a specific enhancement of correlated movements in EGF4. These data provide atomistic-level clues of how natural regulators of Wnt signaling manipulate LRP6 dynamics and, therefore, guide the structure-based design of efficient artificial inhibitors/activators for the pathway.

The ultimate microbial composition for correcting Th17/Treg cell imbalance and lipid metabolism disorders in osteoporosis

Osteoporosis is a systemic bone disease characterised by decreased bone mass and a deteriorated bone microstructure, leading to increased bone fragility and fracture risk. Disorders of the intestinal microbiota may be key inducers of osteoporosis. Furthermore, such disorders may contribute to osteoporosis by influencing immune function and lipid metabolism. Therefore, in this review, we aimed to summarise the molecular mechanisms through which the intestinal microbiota affect the onset and development of osteoporosis by regulating Th17/Treg imbalance and lipid metabolism disorders. We also discussed the regulatory mechanisms underlying the effect of intestinal microbiota-related modulators on Th17/Treg imbalance and lipid metabolism disorders in osteoporosis, to explore new molecular targets for its treatment and provide a theoretical basis for clinical management.

Aberrant Wnt/β-catenin signaling in the mesenchymal stem cells of LZTFL1-depleted mice leads to increased adipogenesis, with implications for obesity

Obesity is one of the main clinical characteristics associated with the heterogeneous genetic disorder Bardet-Biedl syndrome (BBS). Leucine zipper transcription factor like 1 (LZTFL1) is a member of the BBS gene family. Our work showed that Lztfl1knockout (LZKO) mice display the obesity phenotype as early as 3 months of age. Mesenchymal stem cells (MSCs) are multipotent stem cells that can differentiate into various cell types, including adipocytes. To understand the role of LZTFL1 in adipogenesis, we analyzed MSCs isolated from LZKO mouse compact bones (CB-MSCs). Compared to wildtype (WT), LZKO CB-MSCs had elongated primary cilia with tapered tips and increased levels of peroxisome proliferator-activated receptor γ (PPARγ), a key transcription factor that favors adipogenesis, and nuclear glucocorticoid receptor (GR), a transcription factor involved in Pparg activation. Also, LZKO CB-MSCs had a lower level of total β-catenin, a core factor of the antiadipogenic canonical Wnt/b-catenin signaling pathway involved in limiting the nuclear localization of GR. Interaction between caveolin1 (CAV1) and LRP6, the main receptor for canonical Wnt signaling, is known to be critical for Wnt pathway activation and β-catenin stabilization. Compared to WT cells, LZKO cells had elevated total, cell-surface, and lipid-raft-associated LRP6 and reduced CAV1, strongly indicating alterations in the components of the Wnt-signaling pathway. We show that in the absence of LZTFL1, adipogenesis-restraining Wnt/β-catenin signaling is inhibited, and adipogenesis-favorable factors are stimulated in CB-MSCs, leading to enhanced adipogenesis. Evidence provided here could help in understanding the mechanism and molecular basis of obesity in LZTFL1-defective patients.

Cardiovascular safety of osteoanabolic agents

PURPOSE

Several osteoanabolic agents have been developed to build new bone more efficiently than anti-resorptive drugs. Among them, romosozumab, an anti-sclerostin antibody, is a potent pharmacological tool to prevent fractures in osteoporosis patients. The efficacy of romosozumab in preventing osteoporotic fractures is robust. However, there remains a concern about increased cardiovascular (CV) adverse events related to romosozumab. Available data have been reviewed to address this concern.

METHODS

Published articles on romosozumab of which pivotal randomized controlled trials (RCTs), meta-analyses of RCTs, pharmacovigilance investigations, and retrospective observational clinical studies using real-world data were collected through PubMed and other available tools.

RESULTS

Meta-analyses of RCTs of romosozumab compared to placebo and other anti-osteoporosis drugs have left room for controversy in the CV safety of romosozumab. Investigations of the real-world data also provide no conclusive evidence in this issue.

CONCLUSION

We need more robust evidence to establish an appropriate and reasonable guide to prescribe romosozumab in our clinical practice.

The Complex Connection Between Myocardial Dysfunction and Cancer Beyond Cardiotoxicity: Shared Risk Factors and Common Molecular Pathways

Cardiovascular diseases and cancer represent the largest disease burden worldwide. Previously, these two conditions were considered independent, except in terms of cardiotoxicity, which links cancer treatment to subsequent cardiovascular issues. However, recent studies suggest that there are further connections between cancer and heart disease beyond cardiotoxicity. It has been revealed that myocardial dysfunction may promote carcinogenesis, indicating that additional common pathophysiological mechanisms might be involved in the relationship between cardiology and oncology, rather than simply a connection through cardiotoxic effects. These mechanisms may include shared risk factors and common molecular pathways, such as persistent inflammation and neurohormonal activation. This review explores the connection between myocardial dysfunction and cancer, emphasizing their shared risk factors, similar biological mechanisms, and causative factors like cardiotoxicity, along with their clinical implications.

Early-Onset Osteoporosis: Molecular Analysis in Large Cohort and Focus on the PLS3 Gene

Osteoporosis is a skeletal disorder characterized by abnormal bone microarchitecture and low bone mineral density (BMD), responsible for an increased risk of fractures and skeletal fragility. It is a common pathology of the aging population. However, when osteoporosis occurs in children or young adults, it strongly suggests an underlying genetic etiology. Over the past two decades, several genes have been identified as responsible for this particular kind of considered monogenic early-onset osteoporosis (EOOP) or juvenile osteoporosis, the main ones being COL1A1, COL1A2, LRP5, LRP6, WNT1, and more recently PLS3. In this study, the objective was to characterize a large cohort of patients diagnosed with primary osteoporosis and to establish its diagnosis yield. The study included 577 patients diagnosed with primary osteoporosis and its diagnosis yield was established. To this end, next-generation sequencing (NGS) of a panel of 21 genes known to play a role in bone fragility was carried out. A genetic etiology was explained in about 18% of cases, while the others remain unexplained. The most frequently identified gene associated with EOOP is LRP5, which was responsible for 8.2% of the positive results (47 patients). As unexpected, 17 patients (2.9%) had a variant in PLS3 which encodes plastin 3. Alterations of PLS3 are associated with dominant X-linked osteoporosis, an extremely rare disease. Given the rarity of this disease, we focused on it. It was observed that males were more affected than females, but it is noteworthy that three females with a particularly severe phenotype were identified. Of these three, two had a variant in an additional gene involved in EOP, illustrating the probable existence of digenism. We significantly increase the number of variants potentially associated with EOOP, especially in PLS3. The results of our study demonstrate that molecular analysis in EOOP is beneficial and useful.

Maladaptive regeneration and metabolic dysfunction associated steatotic liver disease: Common mechanisms and potential therapeutic targets

The normal liver has an extraordinary capacity of regeneration. However, this capacity is significantly impaired in steatotic livers. Emerging evidence indicates that metabolic dysfunction associated steatotic liver disease (MASLD) and liver regeneration share several key mechanisms. Some classical liver regeneration pathways, such as HGF/c-Met, EGFR, Wnt/β-catenin and Hippo/YAP-TAZ are affected in MASLD. Some recently established therapeutic targets for MASH such as the Thyroid Hormone (TH) receptors, Glucagon-like protein 1 (GLP1), Farnesoid X receptor (FXR), Peroxisome Proliferator-Activated Receptors (PPARs) as well as Fibroblast Growth Factor 21 (FGF21) are also reported to affect hepatocyte proliferation. With this review we aim to provide insight into common molecular pathways, that may ultimately enable therapeutic strategies that synergistically ameliorate steatohepatitis and improve the regenerating capacity of steatotic livers. With the recent rise of prolonged ex-vivo normothermic liver perfusion prior to organ transplantation such treatment is no longer restricted to patients undergoing major liver resection or transplantation, but may eventually include perfused (steatotic) donor livers or even liver segments, opening hitherto unexplored therapeutic avenues.

Liver microRNA transcriptome reveals miR-182 as link between type 2 diabetes and fatty liver disease in obesity

Background

The development of obesity-associated comorbidities such as type 2 diabetes (T2D) and hepatic steatosis has been linked to selected microRNAs in individual studies; however, an unbiased genome-wide approach to map T2D induced changes in the miRNAs landscape in human liver samples, and a subsequent robust identification and validation of target genes are still missing.

Methods

Liver biopsies from age- and gender-matched obese individuals with (n=20) or without (n=20) T2D were used for microRNA microarray analysis. The candidate microRNA and target genes were validated in 85 human liver samples, and subsequently mechanistically characterized in hepatic cells as well as by dietary interventions and hepatic overexpression in mice.

Results

Here, we present the human hepatic microRNA transcriptome of type 2 diabetes in liver biopsies and use a novel seed prediction tool to robustly identify microRNA target genes, which were then validated in a unique cohort of 85 human livers. Subsequent mouse studies identified a distinct signature of T2D-associated miRNAs, partly conserved in both species. Of those, human-murine miR-182-5 p was the most associated with whole-body glucose homeostasis and hepatic lipid metabolism. Its target gene LRP6 was consistently lower expressed in livers of obese T2D humans and mice as well as under conditions of miR-182-5 p overexpression. Weight loss in obese mice decreased hepatic miR-182-5 p and restored Lrp6 expression and other miR-182-5 p target genes. Hepatic overexpression of miR-182-5 p in mice rapidly decreased LRP6 protein levels and increased liver triglycerides and fasting insulin under obesogenic conditions after only seven days.

Conclusions

By mapping the hepatic miRNA-transcriptome of type 2 diabetic obese subjects, validating conserved miRNAs in diet-induced mice, and establishing a novel miRNA prediction tool, we provide a robust and unique resource that will pave the way for future studies in the field. As proof of concept, we revealed that the repression of LRP6 by miR-182-5 p, which promotes lipogenesis and impairs glucose homeostasis, provides a novel mechanistic link between T2D and non-alcoholic fatty liver disease, and demonstrate in vivo that miR-182-5 p can serve as a future drug target for the treatment of obesity-driven hepatic steatosis.

Funding

This work was supported by research funding from the Deutsche Forschungsgemeinschaft (KI 1887/2-1, KI 1887/2-2, KI 1887/3-1 and CRC-TR296), the European Research Council (ERC, CoG Yoyo LepReSens no. 101002247; PTP), the Helmholtz Association (Initiative and Networking Fund International Helmholtz Research School for Diabetes; MB) and the German Center for Diabetes Research (DZD Next Grant 82DZD09D1G).

What Causes Premature Coronary Artery Disease?

PURPOSE OF REVIEW

This review provides an overview of genetic and non-genetic causes of premature coronary artery disease (pCAD).

RECENT FINDINGS

pCAD refers to coronary artery disease (CAD) occurring before the age of 65 years in women and 55 years in men. Both genetic and non-genetic risk factors may contribute to the onset of pCAD. Recent advances in the genetic epidemiology of pCAD have revealed the importance of both monogenic and polygenic contributions to pCAD. Familial hypercholesterolemia (FH) is the most common monogenic disorder associated with atherosclerotic pCAD. However, clinical overreliance on monogenic genes can result in overlooked genetic causes of pCAD, especially polygenic contributions. Non-genetic factors, notably smoking and drug use, are also important contributors to pCAD. Cigarette smoking has been observed in 25.5% of pCAD patients relative to 12.2% of non-pCAD patients. Finally, myocardial infarction (MI) associated with spontaneous coronary artery dissection (SCAD) may result in similar clinical presentations as atherosclerotic pCAD. Recognizing the genetic and non-genetic causes underlying pCAD is important for appropriate prevention and treatment. Despite recent progress, pCAD remains incompletely understood, highlighting the need for both awareness and research.

Novel variant in LRP6 associated with unusual and severe clinical presentation: Case report

Low-density lipoprotein receptor-related protein 6 (LRP6) is a co-receptor of the Wnt signaling pathway, which plays an essential role in various biological activities during embryonic and postnatal development. LRP6 is exceptionally associated with rare diseases and always with autosomal dominant inheritance. Here we report a familial phenotype of high bone mass associated with skeletal anomalies and oligodontia but also persistent left superior vena cava, inguinal hernia, hepatic cysts, abnormal posterior fossa and genital malformations. Molecular analysis revealed a novel heterozygous variant, NM_002336.2: c.724T>C, p.(Trp242Arg), in affected individuals. This variant is located in the first β-propellant motif of LRP6, to which sclerostin (SOST) and dickkopf1 (DKK1), two LRP6 co-receptor inhibitors and various Wnt ligands bind. According to the literature and integrating data from structural analysis, this variant distorts the binding of SOST and DKK1, thus leading to overactivation of Wnt signaling pathways involved in osteoblast differentiation. This novel heterozygous variant in LRP6 underlies the role of LRP6 in skeletal and dental disorders as well as, probably, cardiac, cerebral and genital developments.

Contribution of genetic variants in the development of familial premature coronary artery disease in a cohort of cardiac patients

Coronary artery disease (CAD), the most prevalent cardiovascular disease, is the leading cause of death worldwide. Heritable factors play a significant role in the pathogenesis of CAD. It has been proposed that approximately one-third of patients with CAD have a positive family history, and individuals with such history are at ~1.5-fold increased risk of CAD in their lifespans. Accordingly, the long-recognized familial clustering of CAD is a strong risk factor for this disease. Our study aimed to identify candidate genetic variants contributing to CAD by studying a cohort of 60 large Iranian families with at least two members in different generations afflicted with premature CAD (PCAD), defined as established disease at ≤45 years in men and ≤55 years in women. Exome sequencing was performed for a subset of the affected individuals, followed by prioritization and Sanger sequencing of candidate variants in all available family members. Subsequently, apparently healthy carriers of potential risk variants underwent coronary computed tomography angiography (CCTA), followed by co-segregation analysis of the combined data. Putative causal variants were identified in seven genes, ABCG8, CD36, CYP27A1, PIK3C2G, RASSF9, RYR2, and ZFYVE21, co-segregating with familial PCAD in seven unrelated families. Among these, PIK3C2G, RASSF9, and ZFYVE21 are novel candidate CAD susceptibility genes. Our findings indicate that rare variants in genes identified in this study are involved in CAD development.

WNT Signaling Cascade Proteins and LRP6 in the Formation of Various Types of Coronary Lesions in Patients With Coronary Artery Disease

AIM

Assessment of WNT1, WNT3a, and LRP6 concentrations in patients with ischemic heart disease (IHD) and obstructive and non-obstructive coronary artery (CA) disease.

MATERIAL AND METHODS

This cross-sectional observational study included 50 IHD patients (verified by coronary angiography, CAG), of which 25 (50%) were men, mean age 64.9±8.1 years; 20 patients had non-obstructive CA disease (stenosis <50%), and 30 patients had hemodynamically significant stenosis. Concentrations of WNT1, WNT3a and LRP6 were measured in all patients.

RESULTS

The concentrations of WNT1 and WNT3a proteins were significantly higher in patients with IHD and obstructive CA disease (p < 0.001), while the concentration of LRP6 was higher in the group with non-obstructive CA disease (p = 0.016). Data analysis of the group with obstructive CA disease showed a moderate correlation between WNT1 and LRP6 (ρ=0.374; p=0.042). Correlation analysis of all groups of patients with CA disease revealed a moderate association between the concentrations of WNT1 and uric acid (ρ=0.416; p=0.007). Regression analysis showed that risk factors for the development of IHD, such as increased body mass index, age, smoking, dyslipidemia, and hypertension, did not significantly influence the type of CA disease in IHD patients. According to ROC analysis, the obstructive form of IHD was predicted by a WNT3a concentration higher than 0.155 ng/ml and a LRP6 concentration lower than 12.94 ng/ml.

CONCLUSION

IHD patients with non-obstructive CA disease had the greatest increase in LRP6, while patients with obstructive CA disease had significantly higher concentrations of the canonical WNT cascade proteins, WNT1 and WNT3a. According to the ROC analysis, a WNT3a concentration >0.155 ng/ml can serve as a predictor for the presence of hemodynamically significant CA stenosis in IHD patients (sensitivity 96.7%; specificity 70%), whereas a LRP6 concentration >12.94 ng/ml can predict the development of non-obstructive CA disease (sensitivity 76.7%; specificity 65%).

Identification of Transcripts with Shared Roles in the Pathogenesis of Postmenopausal Osteoporosis and Cardiovascular Disease

Epidemiological evidence suggests existing comorbidity between postmenopausal osteoporosis (OP) and cardiovascular disease (CVD), but identification of possible shared genes is lacking. The skeletal global transcriptomes were analyzed in trans-iliac bone biopsies (n = 84) from clinically well-characterized postmenopausal women (50 to 86 years) without clinical CVD using microchips and RNA sequencing. One thousand transcripts highly correlated with areal bone mineral density (aBMD) were further analyzed using bioinformatics, and common genes overlapping with CVD and associated biological mechanisms, pathways and functions were identified. Fifty genes (45 mRNAs, 5 miRNAs) were discovered with established roles in oxidative stress, inflammatory response, endothelial function, fibrosis, dyslipidemia and osteoblastogenesis/calcification. These pleiotropic genes with possible CVD comorbidity functions were also present in transcriptomes of microvascular endothelial cells and cardiomyocytes and were differentially expressed between healthy and osteoporotic women with fragility fractures. The results were supported by a genetic pleiotropy-informed conditional False Discovery Rate approach identifying any overlap in single nucleotide polymorphisms (SNPs) within several genes encoding aBMD- and CVD-associated transcripts. The study provides transcriptional and genomic evidence for genes of importance for both BMD regulation and CVD risk in a large collection of postmenopausal bone biopsies. Most of the transcripts identified in the CVD risk categories have no previously recognized roles in OP pathogenesis and provide novel avenues for exploring the mechanistic basis for the biological association between CVD and OP.

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

The evolutionarily conserved Wnt signaling pathway plays a central role in development and adult tissue homeostasis across species. Wnt proteins are secreted, lipid-modified signaling molecules that activate the canonical (β-catenin dependent) and non-canonical (β-catenin independent) Wnt signaling pathways. Cellular behaviors such as proliferation, differentiation, maturation, and proper body-axis specification are carried out by the canonical pathway, which is the best characterized of the known Wnt signaling paths. Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues. This includes but is not limited to embryonic, hematopoietic, mesenchymal, gut, neural, and epidermal stem cells. Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties. Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders. Not surprisingly, aberrant Wnt signaling is also associated with a wide variety of diseases, including cancer. Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation, epithelial-mesenchymal transition, and metastasis. Altogether, advances in the understanding of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway. Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt, this review aims to summarize the current knowledge of Wnt signaling in stem cells, aberrations to the Wnt pathway associated with diseases, and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

Update in genetic and epigenetic causes of hypertension

Hypertension is a heritable disease that affects one-fourth of the population and accounts for about 50% of cardiovascular deaths. The genetic basis of hypertension is multifaceted, involving both monogenic and most commonly complex polygenic forms. With the advent of the human genome project, genome-wide association studies (GWAS) have identified a plethora of loci linked to hypertension by examining common genetic variations. It's notable, however, that the majority of these genetic variants do not affect the protein-coding sequences, posing a considerable obstacle in pinpointing the actual genes responsible for hypertension. Despite these challenges, precise mapping of GWAS-identified loci is emerging as a promising strategy to reveal novel genes and potential targets for the pharmacological management of blood pressure. This review provides insight into the monogenic and polygenic causes of hypertension. Special attention is given to PRDM6, among the earliest functionally characterized GWAS-identified genes. Moreover, this review delves into the roles of genes contributing to renal and vascular forms of hypertension, offering insights into their genetic and epigenetic mechanisms of action.

Role of human Kallistatin in glucose and energy homeostasis in mice

OBJECTIVE

Kallistatin (KST), also known as SERPIN A4, is a circulating, broadly acting human plasma protein with pleiotropic properties. Clinical studies in humans revealed reduced KST levels in obesity. The exact role of KST in glucose and energy homeostasis in the setting of insulin resistance and type 2 diabetes is currently unknown.

METHODS

Kallistatin mRNA expression in human subcutaneous white adipose tissue (sWAT) of 47 people with overweight to obesity of the clinical trial "Comparison of Low Fat and Low Carbohydrate Diets With Respect to Weight Loss and Metabolic Effects (B-SMART)" was measured. Moreover, we studied transgenic mice systemically overexpressing human KST (hKST-TG) and wild type littermate control mice (WT) under normal chow (NCD) and high-fat diet (HFD) conditions.

RESULTS

In sWAT of people with overweight to obesity, KST mRNA increased after diet-induced weight loss. On NCD, we did not observe differences between hKST-TG and WT mice. Under HFD conditions, body weight, body fat and liver fat content did not differ between genotypes. Yet, during intraperitoneal glucose tolerance tests (ipGTT) insulin excursions and HOMA-IR were lower in hKST-TG (4.42 ± 0.87 AU, WT vs. 2.20 ± 0.27 AU, hKST-TG, p < 0.05). Hyperinsulinemic euglycemic clamp studies with tracer-labeled glucose infusion confirmed improved insulin sensitivity by higher glucose infusion rates in hKST-TG mice (31.5 ± 1.78 mg/kg/min, hKST-TG vs. 18.1 ± 1.67 mg/kg/min, WT, p < 0.05). Improved insulin sensitivity was driven by reduced hepatic insulin resistance (clamp hepatic glucose output: 7.7 ± 1.9 mg/kg/min, hKST-TG vs 12.2 ± 0.8 mg/kg/min, WT, p < 0.05), providing evidence for direct insulin sensitizing effects of KST for the first time. Insulin sensitivity was differentially affected in skeletal muscle and adipose tissue. Mechanistically, we observed reduced Wnt signaling in the liver but not in skeletal muscle, which may explain the effect.

CONCLUSIONS

KST expression increases after weight loss in sWAT from people with obesity. Furthermore, human KST ameliorates diet-induced hepatic insulin resistance in mice, while differentially affecting skeletal muscle and adipose tissue insulin sensitivity. Thus, KST may be an interesting, yet challenging, therapeutic target for patients with obesity and insulin resistance.

Wnt Signaling in Atherosclerosis: Mechanisms to Therapeutic Implications

Atherosclerosis is a vascular disease in which inflammation plays a pivotal role. Receptor-mediated signaling pathways regulate vascular inflammation and the pathophysiology of atherosclerosis. Emerging evidence has revealed the role of the Wnt pathway in atherosclerosis progression. The Wnt pathway influences almost all stages of atherosclerosis progression, including endothelial dysfunction, monocyte infiltration, smooth muscle cell proliferation and migration, and plaque formation. Targeting the Wnt pathway to treat atherosclerosis represents a promising therapeutic approach that remains understudied. Blocking Wnt signaling utilizing small molecule inhibitors, recombinant proteins, and/or neutralizing antibodies ameliorates atherosclerosis in preclinical models. The Wnt pathway can be potentially manipulated through targeting Wnt ligands, receptors, co-receptors, and downstream signaling molecules. However, there are challenges associated with developing a real world therapeutic compound that targets the Wnt pathway. This review focuses on the role of Wnt signaling in atherosclerosis development, and the rationale for targeting this pathway for the treatment of atherosclerosis.

Wnt16 Promotes Vascular Smooth Muscle Contractile Phenotype and Function via Taz (Wwtr1) Activation in Male LDLR-/- Mice

Wnt16 is expressed in bone and arteries, and maintains bone mass in mice and humans, but its role in cardiovascular physiology is unknown. We show that Wnt16 protein accumulates in murine and human vascular smooth muscle (VSM). WNT16 genotypes that convey risk for bone frailty also convey risk for cardiovascular events in the Dallas Heart Study. Murine Wnt16 deficiency, which causes postnatal bone loss, also reduced systolic blood pressure. Electron microscopy demonstrated abnormal VSM mitochondrial morphology in Wnt16-null mice, with reductions in mitochondrial respiration. Following angiotensin-II (AngII) infusion, thoracic ascending aorta (TAA) dilatation was greater in Wnt16-/- vs Wnt16+/+ mice (LDLR-/- background). Acta2 (vascular smooth muscle alpha actin) deficiency has been shown to impair contractile phenotype and worsen TAA aneurysm with concomitant reductions in blood pressure. Wnt16 deficiency reduced expression of Acta2, SM22 (transgelin), and other contractile genes, and reduced VSM contraction induced by TGFβ. Acta2 and SM22 proteins were reduced in Wnt16-/- VSM as was Ankrd1, a prototypic contractile target of Yap1 and Taz activation via TEA domain (TEAD)-directed transcription. Wnt16-/- VSM exhibited reduced nuclear Taz and Yap1 protein accumulation. SiRNA targeting Wnt16 or Taz, but not Yap1, phenocopied Wnt16 deficiency, and Taz siRNA inhibited contractile gene upregulation by Wnt16. Wnt16 incubation stimulated mitochondrial respiration and contraction (reversed by verteporfin, a Yap/Taz inhibitor). SiRNA targeting Taz inhibitors Ccm2 and Lats1/2 mimicked Wnt16 treatment. Wnt16 stimulated Taz binding to Acta2 chromatin and H3K4me3 methylation. TEAD cognates in the Acta2 promoter conveyed transcriptional responses to Wnt16 and Taz. Wnt16 regulates cardiovascular physiology and VSM contractile phenotype, mediated via Taz signaling.

Huntingtin loss in hepatocytes is associated with altered metabolism, adhesion, and liver zonation

Huntington's disease arises from a toxic gain of function in the huntingtin (HTT) gene. As a result, many HTT-lowering therapies are being pursued in clinical studies, including those that reduce HTT RNA and protein expression in the liver. To investigate potential impacts, we characterized molecular, cellular, and metabolic impacts of chronic HTT lowering in mouse hepatocytes. Lifelong hepatocyte HTT loss is associated with multiple physiological changes, including increased circulating bile acids, cholesterol and urea, hypoglycemia, and impaired adhesion. HTT loss causes a clear shift in the normal zonal patterns of liver gene expression, such that pericentral gene expression is reduced. These alterations in liver zonation in livers lacking HTT are observed at the transcriptional, histological, and plasma metabolite levels. We have extended these phenotypes physiologically with a metabolic challenge of acetaminophen, for which the HTT loss results in toxicity resistance. Our data reveal an unexpected role for HTT in regulating hepatic zonation, and we find that loss of HTT in hepatocytes mimics the phenotypes caused by impaired hepatic β-catenin function.

Evolution of the search for a common mechanism of congenital risk of coronary heart disease and type 2 diabetes mellitus in the chromosomal locus 9p21.3

9.21.3 chromosomal locus predisposes to coronary heart disease (CHD) and type 2 diabetes mellitus (DM2), but their overall pathological mechanism and clinical applicability remain unclear. The review uses publications of the study results of 9.21.3 chromosomal locus in association with CHD and DM2, which are important for changing the focus of clinical practice. The eligibility criteria are full-text articles published in the PubMed database (MEDLINE) up to December 31, 2022. A total of 56 publications were found that met the inclusion criteria. Using the examples of the progressive stages in understanding the role of the chromosomal locus 9p.21.3, scientific ideas were grouped, from a fragmentary study of independent pathological processes to a systematic study of the overall development of CHD and DM2. The presented review can become a source of new scientific hypotheses for further studies, the results of which can determine the general mechanism of the congenital risk of CHD and DM2 and change the focus of clinical practice.

Relationship Between Blood Monocyte-HDL Ratio and Carotid Intima Media Thickness in with Postmenopausal Women

INTRODUCTION/BACKGROUND

The monocyte-to-high-density lipoprotein (HDL) ratio (MHR) and carotid intima media thickness may be used as a marker of inflammation and oxidative stres. This study is aimed to investigate the role of MHR in etiopathogenesis and to determine the association between MHR and carotid intima media thickness, fracture risk, and quality of life (QoL) in postmenopausal osteoporosis patients without comorbidities.

METHODOLOGY

Sixty osteoporosis, sixty osteopenia and sixty control groups were included in the prospective study evaluating postmenapausal women. The monocyte, HDL, and MHR values of all patients were evaluated. The bone mineral density of the participants was determined using the dual energy X-ray absorptiometry device. The fracture risk was assessed using the Turkish model of the Fracture Risk Assessment Tool. The QoL was determined using the Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO-41) scale, and carotid intima media thickness ultrasonography was used.

RESULTS

The age, body mass index, duration of menopause, monocyte, HDL, and MHR were similar in all three groups. carotid intima media thickness was higher in the osteoporosis group than in the normal group (p=0.015). A positive correlation was found between L1-4 total T score and monocytes, major osteoporotic fracture risk and physical function from QUALEFFO-41 sub-headings, MHR and QUALEFFO-41 total score (p<0.05). When all participants were evaluated, a positive correlation was found between femoral neck T score and MHR, L1-4 total T score and monocytes, while a negative correlation was found between L1-4 total T score and CIMT (p<0.05).

CONCLUSION

Among postmenopausal women without comorbidities, MHR in the osteoporosis group was similar to that of the osteopenia and normal groups. Monocyte and MHR correlate with femoral neck T score and L1-4 total T score. CIMT was associated with a decreased L1-4 total T-score and an increased fracture risk, but not with MHR.

AXIN1 bi-allelic variants disrupting the C-terminal DIX domain cause craniometadiaphyseal osteosclerosis with hip dysplasia

Sclerosing skeletal dysplasias result from an imbalance between bone formation and resorption. We identified three homozygous, C-terminally truncating AXIN1 variants in seven individuals from four families affected by macrocephaly, cranial hyperostosis, and vertebral endplate sclerosis. Other frequent findings included hip dysplasia, heart malformations, variable developmental delay, and hematological anomalies. In line with AXIN1 being a central component of the β-catenin destruction complex, analyses of primary and genome-edited cells harboring the truncating variants revealed enhanced basal canonical Wnt pathway activity. All three AXIN1-truncating variants resulted in reduced protein levels and impaired AXIN1 polymerization mediated by its C-terminal DIX domain but partially retained Wnt-inhibitory function upon overexpression. Addition of a tankyrase inhibitor attenuated Wnt overactivity in the AXIN1-mutant model systems. Our data suggest that AXIN1 coordinates the action of osteoblasts and osteoclasts and that tankyrase inhibitors can attenuate the effects of AXIN1 hypomorphic variants.

Rottlerin suppresses lipid accumulation by inhibiting de novo lipogenesis and adipogenesis via LRP6/mTOR/SREBP1C in 3T3-L1 adipocytes

Rottlerin is isolated from Mallotus japonicus, a plant rich in polyphenols. Rottlerin is a selective PKCδ-inhibitor and is also known as an uncoupler of oxidative phosphorylation and anti-neoplastic agent. However, its anti-obesity effect is yet to be established. Therefore, this study tested whether rottlerin inhibits adipogenesis and de novo lipogenesis via the LRP6/mTOR/SREBP1C pathway in 3T3-L1 adipocytes. Rottlerin dramatically decreased lipid accumulation assessed by Oil Red O as evidence to support the cellular phenotype (p < 0.001). Pivotal messenger RNA and protein expressions associated with de novo lipogenesis (SREBP1C, ACC1, FAS, and SCD1) and adipogenesis (PPARγ and C/EBPα) were subsequentially verified by rottlerin in a dose-dependent manner (p < 0.05). Further investigation revealed that rottlerin reduced the AKT/mTOR pathway via diminished total protein of LRP6 (p < 0.05). Collectively, these findings establish a causal link between rottlerin, LRP6, and the altered nutrient-sensing mTOR pathway, in which rottlerin regulates de novo lipogenesis and adipogenesis in white adipocytes.

The role of sclerostin in lipid and glucose metabolism disorders

Lipid and glucose metabolism are critical for human activities, and their disorders can cause diabetes and obesity, two prevalent metabolic diseases. Studies suggest that the bone involved in lipid and glucose metabolism is emerging as an endocrine organ that regulates systemic metabolism through bone-derived molecules. Sclerostin, a protein mainly produced by osteocytes, has been therapeutically targeted by antibodies for treating osteoporosis owing to its ability to inhibit bone formation. Moreover, recent evidence indicates that sclerostin plays a role in lipid and glucose metabolism disorders. Although the effects of sclerostin on bone have been extensively examined and reviewed, its effects on systemic metabolism have not yet been well summarized. In this paper, we provide a systemic review of the effects of sclerostin on lipid and glucose metabolism based on in vitro and in vivo evidence, summarize the research progress on sclerostin, and prospect its potential manipulation for obesity and diabetes treatment.

Mutated CYP17A1 promotes atherosclerosis and early-onset coronary artery disease

BACKGROUND

Coronary artery disease (CAD) is a multi-factor complex trait and is heritable, especially in early-onset families. However, the genetic factors affecting the susceptibility of early-onset CAD are not fully characterized.

METHODS

In the present study, we identified a rare nonsense variant in the CYP17A1 gene from a Chinese Han family with CAD. To validate the effect of this variation on atherosclerosis and early-onset coronary artery disease, we conducted studies on population, cells, and mice.

RESULTS

The mutation precisely congregated with the clinical syndrome in all the affected family members and was absent in unaffected family members and unrelated controls. Similar to the human phenotype, the CYP17A1-deficient mice present the phenotype of metabolic syndrome with hypertension, increased serum glucose concentration, and presentation of central obesity and fatty liver. Furthermore, CYP17A1 knockout mice or CYP17A1 + ApoE double knockout mice developed more atherosclerotic lesions than wild type (WT) with high fat diary. In cell models, CYP17A1 was found to be involved in glucose metabolism by increasing glucose intake and utilization, through activating IGF1/mTOR/HIF1-α signaling way, which was consistent in CYP17A1 knockout mice with impaired glucose tolerance and insulin resistance.

CONCLUSIONS

Through our study of cells, mice and humans, we identified CYP17A1 as a key protein participating in the pathophysiology of the atherosclerotic process and the possible mechanism of CYP17A1 C987X mutation induced atherosclerosis and early-onset CAD involving glucose homeostasis regulation was revealed. Video Abstract.

Huntingtin loss in hepatocytes is associated with altered metabolism, adhesion, and liver zonation

Huntington's disease arises from a toxic gain of function in the huntingtin ( HTT ) gene. As a result, many HTT-lowering therapies are being pursued in clinical studies, including those that reduce HTT RNA and protein expression in the liver. To investigate potential impacts, we characterized molecular, cellular, and metabolic impacts of chronic HTT lowering in mouse hepatocytes. Lifelong hepatocyte HTT loss is associated with multiple physiological changes, including increased circulating bile acids, cholesterol and urea, hypoglycemia, and impaired adhesion. HTT loss causes a clear shift in the normal zonal patterns of liver gene expression, such that pericentral gene expression is reduced. These alterations in liver zonation in livers lacking HTT are observed at the transcriptional, histological and plasma metabolite level. We have extended these phenotypes physiologically with a metabolic challenge of acetaminophen, for which the HTT loss results in toxicity resistance. Our data reveal an unexpected role for HTT in regulating hepatic zonation, and we find that loss of HTT in hepatocytes mimics the phenotypes caused by impaired hepatic β-catenin function.

Human RSPO1 Mutation Represses Beige Adipocyte Thermogenesis and Contributes to Diet-Induced Adiposity

Recent genetic evidence has linked WNT downstream mutations to fat distribution. However, the roles of WNTs in human obesity remain unclear. Here, the authors screen all Wnt-related paracrine factors in 1994 obese cases and 2161 controls using whole-exome sequencing (WES) and identify that 12 obese patients harbor the same mutations in RSPO1 (p.R219W/Q) predisposing to human obesity. RSPO1 is predominantly expressed in visceral fat, primarily in the fibroblast cluster, and is increased with adiposity. Mice overexpressing human RSPO1 in adipose tissues develop obesity under a high-fat diet (HFD) due to reduced brown/beige fat thermogenesis. In contrast, Rspo1 ablation resists HFD-induced adiposity by increasing thermogenesis. Mechanistically, RSPO1 overexpression or administration significantly inhibits adipocyte mitochondrial respiration and thermogenesis via LGR4-Wnt/β-catenin signaling pathway. Importantly, humanized knockin mice carrying the hotspot mutation (p.R219W) display suppressed thermogenesis and recapitulate the adiposity feature of obese carriers. The mutation disrupts RSPO1's electrostatic interaction with the extracellular matrix, leading to excessive RSPO1 release that activates LGR4-Wnt/β-catenin signaling and attenuates thermogenic capacity in differentiated beige adipocytes. Therefore, these findings identify that gain-of-function mutations and excessive expression of RSPO1, acting as a paracrine Wnt activator, suppress fat thermogenesis and contribute to obesity in humans.

LRP6 Bidirectionally Regulates Insulin Sensitivity through Insulin Receptor and S6K Signaling in Rats with CG-IUGR

OBJECTIVE

Intrauterine growth restriction followed by postnatal catch-up growth (CG-IUGR) increases the risk of insulin resistance-related diseases. Low-density lipoprotein receptor-related protein 6 (LRP6) plays a substantial role in glucose metabolism. However, whether LRP6 is involved in the insulin resistance of CG-IUGR is unclear. This study aimed to explore the role of LRP6 in insulin signaling in response to CG-IUGR.

METHODS

The CG-IUGR rat model was established via a maternal gestational nutritional restriction followed by postnatal litter size reduction. The mRNA and protein expression of the components in the insulin pathway, LRP6/β-catenin and mammalian target of rapamycin (mTOR)/S6 kinase (S6K) signaling, was determined. Liver tissues were immunostained for the expression of LRP6 and β-catenin. LRP6 was overexpressed or silenced in primary hepatocytes to explore its role in insulin signaling.

RESULTS

Compared with the control rats, CG-IUGR rats showed higher homeostasis model assessment for insulin resistance (HOMA-IR) index and fasting insulin level, decreased insulin signaling, reduced mTOR/S6K/ insulin receptor substrate-1 (IRS-1) serine307 activity, and decreased LRP6/β-catenin in the liver tissue. The knockdown of LRP6 in hepatocytes from appropriate-for-gestational-age (AGA) rats led to reductions in insulin receptor (IR) signaling and mTOR/S6K/IRS-1 serine307 activity. In contrast, LRP6 overexpression in hepatocytes of CG-IUGR rats resulted in elevated IR signaling and mTOR/S6K/IRS-1 serine307 activity.

CONCLUSION

LRP6 regulated the insulin signaling in the CG-IUGR rats via two distinct pathways, IR and mTOR-S6K signaling. LRP6 may be a potential therapeutic target for insulin resistance in CG-IUGR individuals.

LRP6-mediated phosphorylation of connexin43 in myocardial infarction

Ventricular tachycardia (VT) and ventricular fibrillation are most causes of early death in patients with acute myocardial infarction (AMI). Conditional cardiac-specific low-density lipoprotein receptor-related protein 6 (LRP6)-knockout mice with connexin 43 (Cx43) reduction triggered the lethal ventricular arrhythmias. Thus, it is necessary for exploring whether LRP6 and its upstream genes circRNA1615 mediate the phosphorylation of Cx43 in VT of AMI. Here, we showed that circRNA1615 regulated the expression of LRP6 mRNA through sponge adsorption of miR-152-3p. Importantly, LRP6 interference fragments aggravated hypoxia injury of Cx43, while overexpression of LRP6 improved the phosphorylation of Cx43. Subsequently, interference with G-protein alpha subunit (Gα_s) downstream of LRP6 further inhibited the phosphorylation of Cx43, along with increasing VT. Our results demonstrated that LRP6 upstream genes circRNA1615 controlled the damage effect and VT in AMI, and LRP6 mediated the phosphorylation of Cx43 via Gα_s which played a role in VT of AMI.

Risk of fracture in neuromyelitis optica spectrum disorder and multiple sclerosis: a nationwide cohort study in South Korea

PURPOSE

Interest in fractures in patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) has considerably increased in the last decade. However, few studies have compared the incidence of fractures between patients with MS and NMOSD using a nationwide database. This study aimed to evaluate the differences in the risk of fracture between patients with NMOSD and MS compared to that in healthy controls using cohort data from a Korean nationwide database.

METHODS

In this retrospective cohort study, data from the National Health Insurance Service (NHIS) database from January 2010 to December 2017 were analyzed. A total of 1,217/1,329 patients with MS/NMOSD free of fractures at the index date were included. Matched controls were selected based on age, sex, and the presence of hypertension, diabetes mellitus, and dyslipidemia. The mean follow-up durations after the index date were 4.40/4.08 years for patients with MS/NMOSD and 4.73/4.28 for their matched controls.

RESULTS

The adjusted hazard ratios (aHRs) with 95% confidence intervals of any, hip, and vertebral fractures were 1.81 (1.43-2.28), 3.36 (1.81-6.24), and 2.01 (1.42-2.99) times higher for patients with MS than for controls, respectively, and they were 1.85 (1.47-2.34), 3.82 (2.05-7.11), and 2.84 (1.92-4.21) times higher for patients with NMOSD than for controls, respectively. No significant differences were observed in the incidence of fractures between the MS and NMOSD groups. Patients with MS/NMOSD had a 1.8-fold higher risk of fracture than matched controls, and the risk of hip fracture was especially high (3- to 4-fold higher).

CONCLUSIONS

Clinicians need to regularly assess patients with MS/NMOSD for the risk of fractures and take preventative measures to reduce it.

Loss of Hepatic Leucine-Rich Repeat-Containing G-Protein Coupled Receptors 4 and 5 Promotes Nonalcoholic Fatty Liver Disease

The roof plate-specific spondin-leucine-rich repeat-containing G-protein coupled receptor 4/5 (LGR4/5)-zinc and ring finger 3 (ZNRF3)/ring finger protein 43 (RNF43) module is a master regulator of hepatic Wnt/β-catenin signaling and metabolic zonation. However, its impact on nonalcoholic fatty liver disease (NAFLD) remains unclear. The current study investigated whether hepatic epithelial cell-specific loss of the Wnt/β-catenin modulator Lgr4/5 promoted NAFLD. The 3- and 6-month-old mice with hepatic epithelial cell-specific deletion of both receptors Lgr4/5 (Lgr4/5dLKO) were compared with control mice fed with normal diet (ND) or high-fat diet (HFD). Six-month-old HFD-fed Lgr4/5dLKO mice developed hepatic steatosis and fibrosis but the control mice did not. Serum cholesterol-high-density lipoprotein and total cholesterol levels in 3- and 6-month-old HFD-fed Lgr4/5dLKO mice were decreased compared with those in control mice. An ex vivo primary hepatocyte culture assay and a comprehensive bile acid (BA) characterization in liver, plasma, bile, and feces demonstrated that ND-fed Lgr4/5dLKO mice had impaired BA secretion, predisposing them to develop cholestatic characteristics. Lipidome and RNA-sequencing analyses demonstrated severe alterations in several lipid species and pathways controlling lipid metabolism in the livers of Lgr4/5dLKO mice. In conclusion, loss of hepatic Wnt/β-catenin activity by Lgr4/5 deletion led to loss of BA secretion, cholestatic features, altered lipid homeostasis, and deregulation of lipoprotein pathways. Both BA and intrinsic lipid alterations contributed to the onset of NAFLD.

Receptors that bind to PEDF and their therapeutic roles in retinal diseases

Retinal neovascular, neurodegenerative, and inflammatory diseases represented by diabetic retinopathy are the main types of blinding eye disorders that continually cause the increased burden worldwide. Pigment epithelium-derived factor (PEDF) is an endogenous factor with multiple effects including neurotrophic activity, anti-angiogenesis, anti-tumorigenesis, and anti-inflammatory activity. PEDF activity depends on the interaction with the proteins on the cell surface. At present, seven independent receptors, including adipose triglyceride lipase, laminin receptor, lipoprotein receptor-related protein, plexin domain-containing 1, plexin domain-containing 2, F1-ATP synthase, and vascular endothelial growth factor receptor 2, have been demonstrated and confirmed to be high affinity receptors for PEDF. Understanding the interactions between PEDF and PEDF receptors, their roles in normal cellular metabolism and the response the initiate in disease will be accommodating for elucidating the ways in which inflammation, angiogenesis, and neurodegeneration exacerbate disease pathology. In this review, we firstly introduce PEDF receptors comprehensively, focusing particularly on their expression pattern, ligands, related diseases, and signal transduction pathways, respectively. We also discuss the interactive ways of PEDF and receptors to expand the prospective understanding of PEDF receptors in the diagnosis and treatment of retinal diseases.

Molecular Mechanisms of Vascular Health: Insights From Vascular Aging and Calcification

Cardiovascular disease is the most common cause of death worldwide, especially beyond the age of 65 years, with the vast majority of morbidity and mortality due to myocardial infarction and stroke. Vascular pathology stems from a combination of genetic risk, environmental factors, and the biologic changes associated with aging. The pathogenesis underlying the development of vascular aging, and vascular calcification with aging, in particular, is still not fully understood. Accumulating data suggests that genetic risk, likely compounded by epigenetic modifications, environmental factors, including diabetes and chronic kidney disease, and the plasticity of vascular smooth muscle cells to acquire an osteogenic phenotype are major determinants of age-associated vascular calcification. Understanding the molecular mechanisms underlying genetic and modifiable risk factors in regulating age-associated vascular pathology may inspire strategies to promote healthy vascular aging. This article summarizes current knowledge of concepts and mechanisms of age-associated vascular disease, with an emphasis on vascular calcification.

Correlation between serum Dickkopf-1 (DKK1) levels and coronary artery stenosis

BACKGROUND AND AIMS

To study the correlation between the level of serum Dickkopf-1 (DKK1) and the degree of coronary artery stenosis in patients with coronary atherosclerotic heart disease.

METHODS AND RESULTS

In 2018, general data and biochemical indexes of 311 patients who underwent coronary angiography were recorded. Before procedure, arterial blood was drawn and the concentrations of DKK1, retinol binding protein 4 (RBP4), plasminogen activator inhibitor (PAI-1) were measured. Based on coronary angiography results, subjects were divided into a coronary heart disease (CHD) group; and a non-coronary heart disease (non-CHD)group. The CHD group was divided into three subgroups: the low Gensini score; the middle Gensini score; and the high Gensini score subgroups. Compared with those of the non-CHD group, DKK1, RBP4 and PAI-1 of the CHD group were significantly higher, while the OC was lower. DKK1,RBP4 and PAI-1 levels of the middle and high Gensini subgroups were significantly higher, compared with that of the low Gensini subgroup. Differences between osteocalcin (OC), beta-isomerized C-terminal telopeptidase (β-CTX), and 25(OH)₂D₃ of the three subgroups were not significant. Correlation between DKK1 and the inflammatory factors, RBP4 and PAI-1, was positive. Correlation between DKK1 and β - CTX, 25(OH)₂D₃ and OC was not significant. DKK1 was a risk factor for CHD. The degree of coronary artery stenosis was related to DKK1 concentration.

CONCLUSIONS

Serum DKK1 levels in coronary heart disease patients were significantly higher, and positively correlated with the degree of coronary artery stenosis. DKK1 level is an independent risk factor for coronary heart disease.

Non-canonical WNT signalling in cardiovascular disease: mechanisms and therapeutic implications

WNT signalling comprises a diverse spectrum of receptor-mediated pathways activated by a large family of WNT ligands and influencing fundamental biological processes. WNT signalling includes the β-catenin canonical pathway and the non-canonical pathways, namely the planar cell polarity and the calcium-dependent pathways. Advances over the past decade have linked non-canonical WNT signalling with key mechanisms of atherosclerosis, including oxidative stress, endothelial dysfunction, macrophage activation and vascular smooth muscle cell phenotype regulation. In addition, non-canonical WNT signalling is involved in crucial aspects of myocardial biology, from fibrosis to hypertrophy and oxidative stress. Importantly, non-canonical WNT signalling activation has complex effects in adipose tissue in the context of obesity, thereby potentially linking metabolic and vascular diseases. Tissue-specific targeting of non-canonical WNT signalling might be associated with substantial risks of off-target tumorigenesis, challenging its therapeutic potential. However, novel technologies, such as monoclonal antibodies, recombinant decoy receptors, tissue-specific gene silencing with small interfering RNAs and gene editing with CRISPR-Cas9, might enable more efficient therapeutic targeting of WNT signalling in the cardiovascular system. In this Review, we summarize the components of non-canonical WNT signalling, their links with the main mechanisms of atherosclerosis, heart failure and arrhythmias, and the rationale for targeting individual components of non-canonical WNT signalling for the treatment of cardiovascular disease.

Osteoblast/osteocyte-derived interleukin-11 regulates osteogenesis and systemic adipogenesis

Exercise results in mechanical loading of the bone and stimulates energy expenditure in the adipose tissue. It is therefore likely that the bone secretes factors to communicate with adipose tissue in response to mechanical loading. Interleukin (IL)-11 is known to be expressed in the bone, it is upregulated by mechanical loading, enhances osteogenesis and suppresses adipogenesis. Here, we show that systemic IL-11 deletion (IL-11^-/-) results in reduced bone mass, suppressed bone formation response to mechanical loading, enhanced expression of Wnt inhibitors, and suppressed Wnt signaling. At the same time, the enhancement of bone resorption by mechanical unloading was unaffected. Unexpectedly, IL-11^-/- mice have increased systemic adiposity and glucose intolerance. Osteoblast/osteocyte-specific IL-11 deletion in osteocalcin-Cre;IL-11^fl/fl mice have reduced serum IL-11 levels, blunted bone formation under mechanical loading, and increased systemic adiposity similar to IL-11^-/- mice. Adipocyte-specific IL-11 deletion in adiponectin-Cre;IL-11^fl/fl did not exhibit any abnormalities. We demonstrate that osteoblast/osteocyte-derived IL-11 controls both osteogenesis and systemic adiposity in response to mechanical loading, an important insight for our understanding of osteoporosis and metabolic syndromes.

Functional Association of miR-133b and miR-21 Through Novel Gene Targets ATG5, LRP6 and SGPP1 in Coronary Artery Disease

BACKGROUND

Atherosclerosis, a progressive manifestation of coronary artery disease, has been observed to be regulated by microRNAs (miRNAs) targeting various protein-coding genes involved in several pathophysiological events of coronary artery disease.

OBJECTIVE

In our previous report, we identified differential expression profiles of candidate miRNAs, miR-133b and miR-21, in patients with coronary artery disease as compared with controls, suggesting their possible implication in the pathophysiology of coronary artery disease. To better understand the functional role of these miRNAs, we sought to predict and validate their target genes while assessing the expression pattern of these genes in patients with coronary artery disease, as well as in macrophages.

METHODS

Potential target genes of miR-133b and miR-21 were predicted bioinformatically followed by validation through the identification of their expression at  the protein level in patients with coronary artery disease (n-30), as well as in macrophages treated with respective miRNA inhibitors (antagomiRs), through immunoblotting.

RESULTS

SGPP1, a gene associated with the sphingolipid pathway, was predicted to be a potential target gene of miR-133b while ATG5 and LRP6 were target genes of miR-21 while being associated with autophagy and Wnt signalling pathways, respectively. SGPP1 was observed to be upregulated significantly (p = 0.019) by 2.07-fold, whereas ATG5 and LRP6 were found to be downregulated (p = 0.026 and 0.007, respectively) by 3.28-fold and 8.46-fold, respectively, in patients with coronary artery disease as compared with controls. Expression patterns of all the genes were also found to be modulated when cells were treated with respective miRNA inhibitors.

CONCLUSIONS

Results from the present study suggest that SGPP1, ATG5 and LRP6, target genes of miR-133b and miR-21, may serve as potential therapeutic hotspots in the management of coronary artery disease, which undoubtedly merit further experimental confirmation.

Coronary artery disease and cancer: a significant resemblance

Cancer and coronary artery disease (CAD) are two of the most common causes of death, and they frequently coexist, especially as the world's population ages. CAD can develop prior to or following cancer diagnosis, as well as a side effect of cancer treatment. CAD develops as complex interactions of lifestyle and hereditary variables, just like the development of the most complex and non-communicable diseases. Cancer is caused by both external/acquired factors (tobacco, food, physical activity, alcohol consumption, epigenetic alterations) and internal/inherited factors (genetic mutations, hormones, and immunological diseases). The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated protein 9 (Cas9) system has recently emerged as a strong tool for gene therapy for both cancer as well as CAD treatment due to its great accuracy and efficiency. A deeper understanding of the complex link between CAD and cancer should lead to better prevention, faster detection, and safer treatment strategies.

PCSK9 and LRP6: potential combination targets to prevent and reduce atherosclerosis

Coronary artery disease (CAD) is a disease characterized by atherosclerosis formation which causes sudden cardiac death. The prevalence of CAD is expected to increase by 2030. Atherosclerosis started from accumulation of LDL in the blood vessels, followed by endothelial cell activation and dysfunction. PCSK9 is a gene that plays an important role in the creation of atherosclerotic plaque through induced degradation of LDLRs. Inhibition of PCSK9 gene resulted in a decrease of LDLRs degradation and reduction in LDL-C levels. LRP6, as well as its mutation, is a coreceptor that contributes to atherosclerosis through the canonical Wnt/β-catenin pathway. By employing EMPs mediated miRNA-126, third-generation antisense against miR-494-3p (3 GA-494), and recombinant Wnt mouse Wnt3a (rmWnt3a), the inhibition of LRP6 could reduce VSMCs proliferation, enhancing anti-inflammatory macrophages, and diminished bioactive lipids component, respectively. Those mechanisms lead to the stabilization and reduction of atherosclerosis plaques.

Phenotypic and Genetic Evidence for a More Prominent Role of Blood Glucose than Cholesterol in Atherosclerosis of Hyperlipidemic Mice

Hyperlipidemia and type 2 diabetes (T2D) are major risk factors for atherosclerosis. Apoe-deficient (Apoe−/−) mice on certain genetic backgrounds develop hyperlipidemia, atherosclerosis, and T2D when fed a Western diet. Here, we sought to dissect phenotypic and genetic relationships of blood lipids and glucose with atherosclerotic plaque formation when the vasculature is exposed to high levels of cholesterol and glucose. Male F2 mice were generated from LP/J and BALB/cJ Apoe−/− mice and fed a Western diet for 12 weeks. Three significant QTL Ath51, Ath52 and Ath53 on chromosomes (Chr) 3 and 15 were mapped for atherosclerotic lesions. Ath52 on proximal Chr15 overlapped with QTL for plasma glucose, non-HDL cholesterol, and triglyceride. Atherosclerotic lesion sizes showed significant correlations with fasting, non-fasting glucose, non-fasting triglyceride, and body weight but no correlation with HDL, non-HDL cholesterol, and fasting triglyceride levels. Ath52 for atherosclerosis was down-graded from significant to suggestive level after adjustment for fasting, non-fasting glucose, and non-fasting triglyceride but minimally affected by HDL, non-HDL cholesterol, and fasting triglyceride. Adjustment for body weight suppressed Ath52 but elevated Ath53 on distal Chr15. These results demonstrate phenotypic and genetic connections of blood glucose and triglyceride with atherosclerosis, and suggest a more prominent role for blood glucose than cholesterol in atherosclerotic plaque formation of hyperlipidemic mice.

Mutation analysis in patients with nonsyndromic tooth agenesis using exome sequencing

BACKGROUND

Tooth agenesis (TA) is a congenital abnormality that may present as syndromic or nonsyndromic. Considering its complex genetic aetiology, the aim of this study was to uncover the pathogenic mutants in patients with nonsyndromic TA and analyse the characteristics of these mutants.

METHODS

Exome sequencing was performed to detect pathogenic variants in 72 patients from 43 unrelated families with nonsyndromic TA. All candidate variants were validated using Sanger sequencing. Bioinformatics and conformational analyses were performed to determine the pathogenic mechanisms of the mutants.

RESULTS

The following eight mutations (six novel and two known) in six genes were identified in eight families: WNT10A [c.742C > T (p.R248*)], LRP6 [c.1518G > A (p.W506*), c.2791 + 1G > T], AXIN2 [c.133_134insGCCAGG (p.44_45insGQ)], PAX9 [c.439C > T (p.Q147*), c.453_454insCCAGC (p.L154QfsTer60)], MSX1 [c.603_604del (p.A203GfsTer10)] and PITX2 [c.522C > G (p.Y174*)]. Bioinformatics and conformational analyses showed that the protein structures were severely altered in these mutants, and indicated that these structural abnormalities may cause functional disabilities.

CONCLUSIONS

Our study extends the mutation spectrum in patients with nonsyndromic TA and provides valuable data for genetic counselling. The pathogenic mechanisms of TA in patients/families with unknown causative variants need to be explored further.

An analytical pathway of consumption expenditure with neighborhood deprivation and depression on cognitive health among elderly in India: A moderated mediation approach

BACKGROUND

This study aims to find the linkage between neighborhood deprivation and cognition with depression as a mediating factor while economic condition as a moderator.

METHODS

We have used the recent baseline wave-1 data of Longitudinal Aging Study in India (LASI), 2017-2018. The study was restricted to 60 and above population, consisting of males (14,931) and females (16,533). We have used moderated mediating model to understand the relationship between deprivation (X), cognition (Y) mediated through depression (M), moderated by economic condition (W), while controlling all possible confounders.

RESULTS

Neighborhood deprivation was positively associated with depression (β: 0.12; SE: 0.01) and inversely linked to cognition (β: -0.4; SE: 0.02). Deprivation had a strong indirect effect on cognition that was mediated by depression. Further, interaction of depression (M) and economic condition (W) was negatively associated (β = -0.03; SE: 0.01) with cognition (Y), indicating that lower economic section being more depressed with lower cognitive function.

LIMITATIONS

The study failed to capture other mental health aspects like stress and anxiety using the Depression, Anxiety and Stress Scale-21 items (DASS-21).

CONCLUSIONS

This study has found a link between higher economic condition with low deprivation and depression. Older individuals with better financial situation have improved cognitive level than their counterparts, who are also depressed. This study provides an opportunity to conduct future research on cognitive health in the face of population aging in India.

Genetic Diagnostics in Routine Osteological Assessment of Adult Low Bone Mass Disorders

CONTEXT

Many different inherited and acquired conditions can result in premature bone fragility/low bone mass disorders (LBMDs).

OBJECTIVE

We aimed to elucidate the impact of genetic testing on differential diagnosis of adult LBMDs and at defining clinical criteria for predicting monogenic forms.

METHODS

Four clinical centers broadly recruited a cohort of 394 unrelated adult women before menopause and men younger than 55 years with a bone mineral density (BMD) Z-score < -2.0 and/or pathological fractures. After exclusion of secondary causes or unequivocal clinical/biochemical hallmarks of monogenic LBMDs, all participants were genotyped by targeted next-generation sequencing.

RESULTS

In total, 20.8% of the participants carried rare disease-causing variants (DCVs) in genes known to cause osteogenesis imperfecta (COL1A1, COL1A2), hypophosphatasia (ALPL), and early-onset osteoporosis (LRP5, PLS3, and WNT1). In addition, we identified rare DCVs in ENPP1, LMNA, NOTCH2, and ZNF469. Three individuals had autosomal recessive, 75 autosomal dominant, and 4 X-linked disorders. A total of 9.7% of the participants harbored variants of unknown significance. A regression analysis revealed that the likelihood of detecting a DCV correlated with a positive family history of osteoporosis, peripheral fractures (> 2), and a high normal body mass index (BMI). In contrast, mutation frequencies did not correlate with age, prevalent vertebral fractures, BMD, or biochemical parameters. In individuals without monogenic disease-causing rare variants, common variants predisposing for low BMD (eg, in LRP5) were overrepresented.

CONCLUSION

The overlapping spectra of monogenic adult LBMD can be easily disentangled by genetic testing and the proposed clinical criteria can help to maximize the diagnostic yield.

Etiologic Puzzle of Coronary Artery Disease: How Important Is Genetic Component?

In the modern era, coronary artery disease (CAD) has become the most common form of heart disease and, due to the severity of its clinical manifestations and its acute complications, is a major cause of morbidity and mortality worldwide. The phenotypic variability of CAD is correlated with the complex etiology, multifactorial (caused by the interaction of genetic and environmental factors) but also monogenic. The purpose of this review is to present the genetic factors involved in the etiology of CAD and their relationship to the pathogenic mechanisms of the disease. Method: we analyzed data from the literature, starting with candidate gene-based association studies, then continuing with extensive association studies such as Genome-Wide Association Studies (GWAS) and Whole Exome Sequencing (WES). The results of these studies revealed that the number of genetic factors involved in CAD etiology is impressive. The identification of new genetic factors through GWASs offers new perspectives on understanding the complex pathophysiological mechanisms that determine CAD. In conclusion, deciphering the genetic architecture of CAD by extended genomic analysis (GWAS/WES) will establish new therapeutic targets and lead to the development of new treatments. The identification of individuals at high risk for CAD using polygenic risk scores (PRS) will allow early prophylactic measures and personalized therapy to improve their prognosis.

Metabolism and Endocrine Disorders: What Wnt Wrong?

A fundamental question in cell biology underlies how nutrients are regenerated to maintain and renew tissues. Physiologically, the canonical Wnt signaling is a vital pathway for cell growth, tissue remodeling, and organ formation; pathologically, Wnt signaling contributes to the development of myriad human diseases such as cancer. Despite being the focus of intense research, how Wnt intersects with the metabolic networks to promote tissue growth and remodeling has remained mysterious. Our understanding of metabolism has been revolutionized by technological advances in the fields of chemical biology, metabolomics, and live microscopy that have now made it possible to visualize and manipulate metabolism in living cells and tissues. The application of these toolsets to innovative model systems have propelled the Wnt field into new realms at the forefront answering the most pressing paradigms of cell metabolism in health and disease states. Elucidating the basis of Wnt signaling and metabolism in a cell-type and tissue-specific manner will provide a powerful base of knowledge for both basic biomedical fields and clinician scientists, and has the promise to generate new, transformative therapies in disease and even processes of aging.