Corticotropin-Releasing Hormone (CRH) Promotes Macrophage Foam Cell Formation via Reduced Expression of ATP Binding Cassette Transporter-1 (ABCA1)

The peripheral corticotropin releasing factor family's role in vasculitis

Corticotropin releasing factor family peptides (CRF peptides) include 4 members, corticotropin releasing hormone (CRH), Urocortin (UCN1), UCN2 and UCN3. CRF peptides function via the two distinct receptors, CRF1 and CRF2. Among them, CRH/CRF1 has been recognized to influence immunity/inflammation peripherally. Both pro- and anti-inflammatory effects of CRH are reported. Likewise, UCNs, peripherally in cardiovascular system have been documented to have both potent protective and harmful effects, with UCN1 acting on both CRF1 & CRF2 and UCN2 & UCN3 on CRF2. We and others also observe protective and detrimental effects of CRF peptides/receptors on vasculature, with the latter of predominantly higher incidence, i.e., they play an important role in the development of vasculitis while in some cases they are found to counteract vascular inflammation. The pro-vasculitis effects of CRH & UCNs include increasing vascular endothelial permeability, interrupting endothelial adherens & tight junctions leading to hyperpermeability, stimulating immune/inflammatory cells to release inflammatory factors, and promoting angiogenesis by VEGF release while the anti-vasculitis effects may be just the opposite, depending on many factors such as different CRF receptor types, species and systemic conditions. Furthermore, CRF peptides' pro-vasculitis effects are found to be likely related to cPLA2 and S1P receptor signal pathway. This minireview will focus on summarizing the peripheral effects of CRF peptides on vasculature participating in the processes of vasculitis.

Psychological stress, the central nervous system and arrhythmias

This review highlights the links between psychological stress and the neurocircuitry of cardiac-brain interactions leading to arrhythmias. The role of efferent and afferent connections in the heart-brain axis is considered, with the mechanisms by which emotional responses promote arrhythmias illustrated by inherited cardiac conditions. Novel therapeutic targets for intervention in the autonomic nervous system are considered.

Neurobiological Basis of Aversion-Resistant Ethanol Seeking in C. elegans

Persistent alcohol seeking despite the risk of aversive consequences is a crucial characteristic of alcohol use disorders (AUDs). Therefore, an improved understanding of the molecular basis of alcohol seeking despite aversive stimuli or punishment in animal models is an important strategy to understand the mechanism that underpins the pathology of AUDs. Aversion-resistant seeking (ARS) is characterized by disruption in control of alcohol use featured by an imbalance between the urge for alcohol and the mediation of aversive stimuli. We exploited C. elegans, a genetically tractable invertebrate, as a model to elucidate genetic components related to this behavior. We assessed the seb-3 neuropeptide system and its transcriptional regulation to progress aversion-resistant ethanol seeking at the system level. Our functional genomic approach preferentially selected molecular components thought to be involved in cholesterol metabolism, and an orthogonal test defined functional roles in ARS through behavioral elucidation. Our findings suggest that fmo-2 (flavin-containing monooxygenase-2) plays a role in the progression of aversion-resistant ethanol seeking in C. elegans.

Large-scale serum analysis identifies unique systemic biomarkers in psoriasis and hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is now recognized as a systemic inflammatory disease, sharing molecular similarities with psoriasis. Direct comparison of the systemic inflammation in HS with psoriasis is lacking.

OBJECTIVES

To evaluate the serum proteome of HS and psoriasis, and to identify biomarkers associated with disease severity.

METHODS

In this cross-sectional study, 1536 serum proteins were assessed using the Olink Explore (Proximity Extension Assay) high-throughput panel in patients with moderate-to-severe HS (n = 11), patients with psoriasis (n = 10) and age- and body mass index-matched healthy controls (n = 10).

RESULTS

HS displayed an overall greater dysregulation of circulating proteins, with 434 differentially expressed proteins (absolute fold change ≥ 1·2; P ≤ 0·05) in patients with HS vs. controls, 138 in patients with psoriasis vs. controls and 503 between patients with HS and patients with psoriasis. Interleukin (IL)-17A levels and T helper (Th)1/Th17 pathway enrichment were comparable between diseases, while HS presented greater tumour necrosis factor- and IL-1β-related signalling. The Th17-associated markers peptidase inhibitor 3 (PI3) and lipocalin 2 (LCN2) were able to differentiate psoriasis from HS accurately. Both diseases presented increases of atherosclerosis-related proteins. Robust correlations between clinical severity scores and immune and atherosclerosis-related proteins were observed across both diseases.

CONCLUSIONS

HS and psoriasis share significant Th1/Th17 enrichment and upregulation of atherosclerosis-related proteins. Despite the greater body surface area involved in psoriasis, HS presents a greater serum inflammatory burden.

Xiaoyaosan (Tiaogan-Liqi therapy) protects peritoneal macrophages from corticosterone-induced stress by regulating the interaction between glucocorticoid receptor and ABCA1

Background

Previous studies have reported that Xiaoyaosan (XYS), Tiaogan-Liqi therapy, has a protective function in depressive disorder, and can regulate body weight and corticosterone (CORT) level. However, little is known about the effect of XYS in treating atherosclerosis. This study aimed to explore the influence XYS on macrophage foam cell formation and related mechanism.

Methods

Rat peritoneal macrophages (PMs) were separated and stimulated with CORT and oxidized low density lipoprotein (ox-LDL). The serum was obtained from rats treated with different doses of XYS and was added into the medium for macrophages. Then, the cell activity and lipid content of PMs were measured through Cell Counting Kit-8 (CCK-8) assay and oil red staining, respectively. The expressions of glucocorticoid receptor (GR), ATP binding cassette subfamily A member 1 (ABCA1), and heat shock protein 90 (HSP90) were detected. In addition, overexpression of GR and ABCA1 was performed and the effect on XYS treatment was subsequently assessed.

Results

The CCK-8 assay showed the serum increased cell activity of CORT-induced stress PMs in a XYS dose-dependent manner. Oil red staining and enzyme-linked immunosorbent assay (ELISA) showed that the serum decreased lipids of PMs. In the XYS treated groups, HSP90 protein was decreased and protein levels of ABCA1 and GR were increased in cytoplasm, while GR protein in nucleus was decreased. Co-immunoprecipitation (Co-IP) assay indicated GR might interact with HSP90 and be involved with the function of XYS. Furthermore, overexpression of GR attenuated the protective function of XYS on CORT-induced stress in PMs, while overexpression of ABCA1 enhanced that.

Conclusions

This study denoted that XYS could protect PMs from CORT-induced stress by regulating the interaction of GR and ABCA1, which might contribute to the treatment of atherosclerosis.

The impact of ATP-binding cassette transporters on metabolic diseases

Currently, many people worldwide suffer from metabolic diseases caused by heredity and external factors, such as diet. One of the symptoms of metabolic diseases is abnormal lipid metabolism. ATP binding cassette (ABC) transporters are one of the largest transport protein superfamilies that exist in nearly all living organisms and are mainly located on lipid-processing cells. ABC transporters have been confirmed to be closely related to the pathogenesis of diseases such as metabolic diseases, cancer and Alzheimer's disease based on their transport abilities. Notably, the capability to transport lipids makes ABC transporters critical in metabolic diseases. In addition, gene polymorphism in ABC transporters has been reported to be a risk factor for metabolic diseases, and it has been reported that relevant miRNAs have significant roles in regulating ABC transporters. In this review, we integrate recent studies to examine the roles of ABC transporters in metabolic diseases and aim to build a network with ABC transporters as the core, linking their transport abilities with metabolic and other diseases.

Analysis of Low Molecular Weight Substances and Related Processes Influencing Cellular Cholesterol Efflux

Cholesterol efflux is the key process protecting the vascular system from the development of atherosclerotic lesions. Various extracellular and intracellular events affect the ability of the cell to efflux excess cholesterol. To explore the possible pathways and processes that promote or inhibit cholesterol efflux, we applied a combined cheminformatic and bioinformatic approach. We performed a comprehensive analysis of published data on the various substances influencing cholesterol efflux and found 153 low molecular weight substances that are included in the Chemical Entities of Biological Interest (ChEBI) database. Pathway enrichment was performed for substances identified within the Reactome database, and 45 substances were selected in 93 significant pathways. The most common pathways included the energy-dependent processes related to active cholesterol transport from the cell, lipoprotein metabolism and lipid transport, and signaling pathways. The activators and inhibitors of cholesterol efflux were non-uniformly distributed among the different pathways: the substances influencing ‘biological oxidations’ activate cholesterol efflux and the substances influencing ‘Signaling by GPCR and PTK6’ inhibit efflux. This analysis may be used in the search and design of efflux effectors for therapies targeting structural and functional high-density lipoprotein deficiency.

Fetal betaine exposure modulates hypothalamic expression of cholesterol metabolic genes in offspring cockerels with modification of promoter DNA methylation

In documents, maternal betaine modulates hypothalamic cholesterol metabolism in chicken posthatchings, but it remains unclear whether this effect can be passed on by generations. In present study, eggs were injected with saline or betaine at 2.5 mg/egg, and the hatchlings (F1) were raised under the same condition until sexual maturation. Both the control group and the betaine group used artificial insemination to collect sperm from their cockerels. Fertilized eggs were incubated, and the hatchlings of the following generation (F2) were raised up to 64 D of age. F2 cockerels in betaine group showed significantly (P < 0.05) lower body weight, which was associated with significantly decreased (P < 0.05) hypothalamic content of total cholesterol and cholesterol ester. Concordantly, hypothalamic expression of cholesterol biosynthetic genes, SREBP2 and HMGCR, were significantly downregulated (P < 0.05), together with cholesterol conversion-related and excretion-related genes, CYP46A1 and ABCA1. These changes coincided with a significant downregulation in mRNA expression of regulatory neuropeptides including brain-derived neurotrophic factor, neuropeptide Y, and corticotropin-releasing hormone. Moreover, genes involved in methyl transfer cycle were also modified. Betaine homocysteine methyltransferase (P < 0.05) was downregulated, yet DNA methyltransferase1 tended to be upregulated (P = 0.06). S-adenosyl methionine/S-adenosylhomocysteine ratio was higher in the hypothalamus of betaine-treated F2 cockerels, which was associated with significantly modified CpG methylation on the promoter of those affected genes. These results suggested that betaine might regulate central cholesterol metabolism and hypothalamic expression of genes related to brain function by altering promoter DNA methylation in F2 cockerels.

N-terminal mutation of apoA-I and interaction with ABCA1 reveal mechanisms of nascent HDL biogenesis

ApoA-I and ABCA1 play important roles in nascent HDL (nHDL) biogenesis, the first step in the pathway of reverse cholesterol transport that protects against cardiovascular disease. On the basis of the crystal structure of a C-terminally truncated form of apoA-I[Δ(185-243)] determined in our laboratory, we hypothesized that opening the N-terminal helix bundle would facilitate lipid binding. To that end, we structurally designed a mutant (L38G/K40G) to destabilize the N-terminal helical bundle at the first hinge region. Conformational characterization of this mutant in solution revealed minimally reduced α-helical content, a less-compact overall structure, and increased lipid-binding ability. In solution-binding studies, apoA-I and purified ABCA1 also showed direct binding between them. In ABCA1-transfected HEK293 cells, L38G/K40G had a significantly enhanced ability to form nHDL, which suggests that a destabilized N-terminal bundle facilitates nHDL formation. The total cholesterol efflux from ABCA1-transfected HEK293 cells was unchanged in mutant versus WT apoA-I, though, which suggests that cholesterol efflux and nHDL particle formation might be uncoupled events. Analysis of the particles in the efflux media revealed a population of apoA-I-free lipid particles along with nHDL. This model improves knowledge of nHDL formation for future research.

Prediction of Molecular Mechanisms for LianXia NingXin Formula: A Network Pharmacology Study

Objectives: Network pharmacological methods were used to investigate the underlying molecular mechanisms of LianXia NingXin (LXNX) formula, a Chinese prescription, to treat coronary heart disease (CHD) and disease phenotypes (CHD related diseases and symptoms).

Methods: The different seed gene lists associated with the herbs of LXNX formula, the CHD co-morbid diseases and symptoms which were relieved by the LXNX formula (co-morbid diseases and symptoms) were curated manually from biomedical databases and published biomedical literatures. Module enrichment analysis was used to identify CHD-related disease modules in the protein–protein interaction (PPI) network which were also associated to the targets of LXNX formula (LXNX formula’s CHD modules). The molecular characteristics of LXNX formula’s CHD modules were investigated via functional enrichment analysis in terms of gene ontology and pathways. We performed shortest path analysis to explore the interactions between the drug targets of LXNX formula and CHD related disease phenotypes (e.g., co-morbid diseases and symptoms).

Results: We identified two significant CHD related disease modules (i.e., M146 and M203), which were targeted by the herbs of LXNX formula. Pathway and GO term functional analysis results indicated that G-protein coupled receptor signaling pathways (GPCR) of M146 and cellular protein metabolic process of M203 are important functional pathways for the respective module. This is further confirmed by the shortest path analysis between the drug targets of LXNX formula and the aforementioned disease modules. In addition, corticotropin releasing hormone (CRH) and natriuretic peptide precursor A (NPPA) are the only two LXNX formula target proteins with the low shortest path length (on average shorter than 3) to their respective CHD module and co-morbid disease and symptom gene groups.

Conclusion: G-protein coupled receptor signaling pathway and cellular protein metabolic process are the key LXNX formula’s pathways to treat CHD disease phenotypes, in which CRH and NPPA are the two key drug targets of LXNX formula. Further evidences from Chinese herb pharmacological databases indicate that Pinellia ternata (Banxia) has relatively strong adjustive functions on the two key targets.

Salidroside protects against foam cell formation and apoptosis, possibly via the MAPK and AKT signaling pathways

BACKGROUND

Foam cell formation and apoptosis are closely associated with atherosclerosis pathogenesis. We determined the effect of salidroside on oxidized low-density lipoprotein (ox-LDL)-induced foam cell formation and apoptosis in THP1 human acute monocytic leukemia cells and investigated the associated molecular mechanisms.

METHODS

THP1-derived macrophages were incubated with salidroside for 5 h and then exposed to ox-LDL for 24 h to induce foam cell formation. Cytotoxicity, lipid deposition, apoptosis, and the expression of various proteins were tested using the CCK8 kit, Oil Red O staining, flow cytometry, and western blotting, respectively.

RESULTS

Ox-LDL treatment alone promoted macrophage-derived foam cell formation, while salidroside treatment alone inhibited it (p < 0.05). The number of early/late apoptotic cells decreased with salidroside treatment in a dose-dependent manner (p < 0.05). Salidroside dramatically upregulated nuclear factor erythroid 2-related factor 2, but had no effect on heme oxygenase-1 expression; moreover, it markedly downregulated ox-LDL receptor 1 and upregulated ATP-binding cassette transporter A1. Salidroside also obviously decreased the phosphorylation of JNK, ERK, p38 MAPK, and increased that of Akt. However, the total expression of these proteins was not affected.

CONCLUSION

Based on our findings, we speculate that salidroside can suppress ox-LDL-induced THP1-derived foam cell formation and apoptosis, partly by regulating the MAPK and Akt signaling pathways.

Gender-specific differences in diabetic neuropathy in BTBR ob/ob mice

AIMS

To identify a female mouse model of diabetic peripheral neuropathy (DPN), we characterized DPN in female BTBR ob/ob mice and compared their phenotype to non-diabetic and gender-matched controls. We also identified dysregulated genes and pathways in sciatic nerve (SCN) and dorsal root ganglia (DRG) of female BTBR ob/ob mice to determine potential DPN mechanisms.

METHODS

Terminal neuropathy phenotyping consisted of examining latency to heat stimuli, sciatic motor and sural sensory nerve conduction velocities (NCV), and intraepidermal nerve fiber (IENF) density. For gene expression profiling, DRG and SCN were dissected, RNA was isolated and processed using microarray technology and differentially expressed genes were identified.

RESULTS

Similar motor and sensory NCV deficits were observed in male and female BTBR ob/ob mice at study termination; however, IENF density was greater in female ob/ob mice than their male counterparts. Male and female ob/ob mice exhibited similar weight gain, hyperglycemia, and hyperinsulinemia compared to non-diabetic controls, although triglycerides were elevated more so in males than in females. Transcriptional profiling of nerve tissue from female mice identified dysregulation of pathways related to inflammation.

CONCLUSIONS

Similar to males, female BTBR ob/ob mice display robust DPN, and pathways related to inflammation are dysregulated in peripheral nerve.