Discovery of Oral AMP-Activated Protein Kinase Activators for Treating Hyperlipidemia.

Activation of AMP-activated protein kinase (AMPK) is proposed to alleviate hyperlipidemia. With cordycepin and N6-(2-hydroxyethyl) adenosine (HEA) as lead compounds, a series of adenosine-based derivatives were designed, synthesized, and evaluated on activation of AMPK. Finally, compound V1 was identified as a potent AMPK activator with the lipid-lowering effect. Molecular docking and circular dichroism indicated that V1 exerted its activity by binding to the γ subunit of AMPK. V1 markedly decreased the serum low-density lipoprotein cholesterol levels in C57BL/6 mice, golden hamsters, and rhesus monkeys. V1 was selected as the clinical compound and concluded Phase 1 clinical trials. A single dose of V1 (2000 mg) increased AMPK activation in human erythrocytes after 5 and 12 h of treatment. RNA sequencing data suggested that V1 downregulated expression of genes involved in regulation of apoptotic process, lipid metabolism, endoplasmic reticulum stress, and inflammatory response in liver by activating AMPK.

Treatment of diabetic peripheral neuropathy with engineered mesenchymal stromal cell-derived exosomes enriched with microRNA-146a provide amplified therapeutic efficacy.

Diabetic peripheral neuropathy (DPN) is one of the most prevalent chronic complications of diabetes mellitus with no effective treatment. We recently demonstrated that mesenchymal stromal cell (MSC)-derived exosomes (exo-naïve) alleviate neurovascular dysfunction and improve functional recovery. MicroRNA (miRNA), one of the exosomal cargos, downregulates inflammation-related genes, resulting in suppression of pro-inflammatory gene activation. In the present study, we developed engineered MSC-exosomes loaded with miR-146a (exo-146a) and compared the therapeutic effects of exo-146a with exo-naïve in diabetic (db/db) mice with DPN. Exo-146a possesses a high loading capacity, robust ability to accumulate in peripheral nerve tissues upon systemic administration, and evokes substantially enhanced therapeutic efficacy on neurological recovery compared with exo-naïve. Treatment of DPN in diabetic mice with exo-146a for two weeks significantly increased and decreased nerve conduction velocity, and thermal and mechanical stimuli threshold, respectively, whereas it took four weeks of exo-naive treatment to achieve these improvements. Compared with exo-naïve, exo-146a significantly suppressed the peripheral blood inflammatory monocytes and the activation of endothelial cells via inhibiting Toll-like receptor (TLR)-4/NF-κB signaling pathway. These data provide a proof-of-concept about both the feasibility and efficacy of the exosome-based gene therapy for DPN. The translation of this approach to the clinic has the potential to improve the prospects for people who suffer from DPN.

Mesenchymal stromal cell-derived exosomes ameliorate peripheral neuropathy in a mouse model of diabetes.

AIMS/HYPOTHESIS: Diabetic peripheral neuropathy (DPN) is one of the major complications of diabetes, which contributes greatly to morbidity and mortality. There is currently no effective treatment for this disease. Exosomes are cell-derived nanovesicles and play an important role in intercellular communications. The present study investigated whether mesenchymal stromal cell (MSC)-derived exosomes improve neurological outcomes of DPN. METHODS: Exosomes were isolated from the medium of cultured mouse MSCs by ultracentrifugation. Diabetic mice (BKS.Cg-m+/+Leprdb/J, db/db) at the age of 20 weeks were used as DPN models. Heterozygous mice (db/m) of the same age were used as the control. MSC-exosomes were administered weekly via the tail vein for 8 weeks. Neurological function was evaluated by testing motor and sensory nerve conduction velocities, and thermal and mechanical sensitivity. Morphometric analysis was performed by myelin sheath staining and immunohistochemistry. Macrophage markers and circulating cytokines were measured by western blot and ELISA. MicroRNA (miRNA) array and bioinformatics analyses were performed to examine the exosomal miRNA profile and miRNA putative target genes involved in DPN. RESULTS: Treatment of DPN with MSC-exosomes markedly decreased the threshold for thermal and mechanical stimuli and increased nerve conduction velocity in diabetic mice. Histopathological analysis showed that MSC-exosomes markedly augmented the density of FITC-dextran perfused blood vessels and increased the number of intraepidermal nerve fibres (IENFs), myelin thickness and axonal diameters of sciatic nerves. Western blot analysis revealed that MSC-exosome treatment decreased and increased M1 and M2 macrophage phenotype markers, respectively. Moreover, MSC-exosomes substantially suppressed proinflammatory cytokines. Bioinformatics analysis revealed that MSC-exosomes contained abundant miRNAs that target the Toll-like receptor (TLR)4/NF-κB signalling pathway. CONCLUSIONS/INTERPRETATION: MSC-derived exosomes alleviate neurovascular dysfunction and improve functional recovery in mice with DPN by suppression of proinflammatory genes.

Inhibition of ABCA1 protein degradation promotes HDL cholesterol efflux capacity and RCT and reduces atherosclerosis in mice.

ABCA1 plays a key role in the initial lipidation of apoA-I, which generates circulating HDL cholesterol. Whereas it is known that the transcriptional upregulation of ABCA1 promotes HDL formation and reverse cholesterol transport (RCT), it is not known how the inhibition of ABCA1 protein degradation impacts HDL function. Employing the small molecule triacetyl-3-hydroxyphenyladenosine (IMM-H007), we determined how the attenuation of ABCA1 protein degradation affects HDL cholesterol efflux capacity, RCT, and atherosclerotic lesion formation. Pulse-chase analysis revealed that IMM-H007 inhibits ABCA1 degradation and facilitates its cell-surface localization in macrophages, and additional studies in macrophages showed that IMM-H007 thereby promotes cholesterol efflux. IMM-H007 treatment of Paigen diet-fed mice caused an increase in circulating HDL level, it increased the cholesterol efflux capacity of HDL, and it enhanced in vivo RCT from macrophages to the plasma, liver, and feces. Furthermore, ABCA1 degradation suppression by IMM-H007 reduced atherosclerotic plaque formation in apoE(-/-) mice. Thus, via effects on both ABCA1-expressing cells and circulating HDL function, the inhibition of ABCA1 protein degradation by IMM-H007 promotes HDL cholesterol efflux capacity and RCT and attenuates atherogenesis. IMM-H007 potentially represents a lead compound for the development of agents to augment HDL function.

Reducing the radiation dose with the adaptive statistical iterative reconstruction technique for chest CT in adults: a parameter study.

BACKGROUND: Currently there is a trend towards reducing radiation dose while maintaining image quality during computer tomography (CT) examination. This results from the concerns about radiation exposure from CT and the potential increase in the incidence of radiation induced carcinogenesis. This study aimed to investigate the lowest radiation dose for maintaining good image quality in adult chest scanning using GE CT equipment. METHODS: Seventy-two adult patients were examined by Gemstone Spectral CT. They were randomly divided into six groups. We set up a different value of noise index (NI) when evaluating each group every other number from 13.0 to 23.0. The original images were acquired with a slice of 5 mm thickness. For each group, several image series were reconstructed using different levels of adaptive statistical iterative reconstruction (ASIR) (30%, 50%, and 70%). We got a total of 18 image sequences of different combinations of NI and ASIR percentage. On one hand, quantitative indicators, such as CT value and standard deviation (SD), were assessed at the region of interest. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The volume CT dose index (CTDI) and dose length product (DLP) were recorded. On the other hand, two radiologists with ≥ 5 years of experience blindly reviewed the subjective image quality using the standards we had previously set. RESULTS: The different combinations of noise index and ASIR were assessed. There was no significant difference in CT values among the 18 image sequences. The SD value was reduced with the noise index's reduction or ASIR's increase. There was a trend towards gradually lower SNR and CNR with an NI increase. The CTDI and DLP were diminishing as the NI increased. The scores from subjective image quality evaluation were reduced in all groups as the ASIR increased. CONCLUSIONS: Increasing NI can reduce radiation dose. With the premise of maintaining the same image quality, using a suitable percentage of ASIR can increase the value of NI. To assure image quality, we concluded that when the NI was set at 17.0 and ASIR was 50%, the image quality could be optimal for not only satisfying the requirements of clinical diagnosis, but also achieving the purpose of low-dose scanning.

[Synthesis and biological evaluation of tetrahydrocoptisine quaternary ammonium compounds].

The goal of treatment of metabolic syndrome is the prevention of diabetes and cardiovascular events. A series of novel tetrahydrocoptisine quaternary ammonium compounds were prepared to evaluate their action of hypoglycemia and hypolipidemia for finding the therapeutic agents of metabolic syndrome. Starting from the coptisine hydrochloride (2), fifteen target compounds were synthesized by reduction and substitution of the 7-N position. All of the target compounds were characterized by 1H NMR and HR-MS. Their hypoglycemic activities were evaluated in HepG2 cell and hypolipidemic activities of compounds with better hypoglycemic activity were tested further in vivo. Results indicated that compounds 5, 7, 8 and 9 exhibited better hypoglycemic activities in vitro and compounds 5 and 8 exhibited good hypolipidemic activities in high-fat-diet (HFD) induced hyperlipidemia mice and (or) hamsters. However, the activity is not as good as simvastatin.