Piperine Attenuates Bmal1-Mediated Glucose Metabolism Disorder in a Trpv1-Dependent Manner in HepG2 Cells

Structure optimization of natural product piperine to obtain novel and potent analogs with anti-inflammation pain and urate-lowering effect

Hyperuricemia is a metabolic disorder syndrome caused by a disorder of purine metabolism in the body, followed by urate crystal deposition leading to gouty arthritis, urate nephropathy, and kidney stones, collectively known as gout. Promoting uric acid stone dissolution by continuously reducing blood uric acid levels and reducing acute gout attacks in patients by controlling inflammatory pain reactions are identified as a potential therapy for gout. Starting from the natural product piperine, three analogs of novel piperine derivates were designed and synthesized to improve the anti-inflammation pain efficacy. Among this, compound 39 exhibited remarkable analgesic and urate-lowering effect in formalin-induced inflammatory pain model and hyperuricemic model, respectively. Besides, compound 39 exhibited a relatively potent TRPV1 antagonistic effect with an IC50 = 33.06 ± 3.15 nM, and moderate to weak URAT1 (IC50 = 22.51 ± 5.62 μM) and GLUT9 inhibitory activities (60.25 % at 50 μM). Further experiment showed that 39 exhibited high stability in vitro and in vivo, and its oral bioavailability was 34 %, with a more than 8 h T1/2. Notably, compound 39 showed high selectivity over other ion channel including hERG which indicated a high safety index. Furthermore, no significant acute damage was observed at the liver microsome, cellular and animal levels. In the long-term administration experiment of hyperuricemia model mice, it was confirmed that 39 could reverse the tissue damage and inflammation caused by high uric acid. Overall, these findings identified a promising candidate to target the pathogenesis of gout by simultaneously suppressing pian and the reabsorption of uric acid.

Regulating Effect and Mechanisms of Piperine on Glucose Homeostasis

Glucose homeostasis is a fundamental physiological process critical for the maintenance of normal cellular functions and overall metabolic health, while disruption of this balance is closely associated with a spectrum of metabolic disorders. Black pepper, one of the world's most widely consumed spices, has been utilized extensively in both traditional medicine and culinary practices, with its bioactive compound piperine (PIP, 1-piperoyl-piperidine), the major alkaloid responsible for its characteristic pungency, emerging as a promising agent for the modulation of glucose metabolism. This Review aims to summarize the regulatory effects of PIP on glucose homeostasis in cell models, animal studies, and human clinical trials as well as the underlying biochemical pathways and molecular mechanisms. This Review highlights PIP as a potentially effective treatment for preventing and managing metabolic disorders associated with disrupted glucose balance, emphasizing its diverse role in influencing various biochemical pathways that control key aspects of glucose metabolism and overall metabolic function.

Capsaicin Mitigates Reverbα-Involved Lipid Metabolism Disorder in HepG2 Cells and Obese Mice through a Trpv1-Dependent Mechanism

Capsaicin (CAP), the active component of chili peppers, exerts a range of health benefits, including anti-inflammatory, antitumor, obesity-prevention, metabolic control, and biological rhythm-modulating effects, primarily through the activation of the transient receptor potential vanilloid 1 (TRPV1) receptor. The research explores the role of TRPV1 and its interaction with hepatic circadian clock regulation in modulating lipid metabolism and liver health. The effect of CAP on lipid metabolism and the potential mechanism was examined in HepG2 cells and high-fat, high-sugar diet (HFFD)-induced obese mice. In vitro, CAP (50 μM) decreased lipid droplet overaccumulation (from 152.8 ± 2.30 to 110.13 ± 3.91%), enhanced mitochondrial function (from 57.94 ± 1.93 to 86.74 ± 1.83%), and alleviated circadian desynchrony through a Trpv1-dependent mechanism in HepG2 cells. In vivo, CAP (5 mg/kg) reduced the body weight gain (from 50.61 ± 3.77 to 38.36 ± 2.04%), restored the hepatic circadian rhythm, and modulated the expression of lipid-related genes through the involvement of TRPV1 in mice. This study highlighted the potential of CAP to attenuate Reverbα-mediated lipid metabolic dysfunction through a Trpv1-dependent mechanism, revealing a complex interplay between circadian regulation and lipid metabolism.

Circadian control of hepatic ischemia/reperfusion injury via HSD17B13-mediated autophagy in hepatocytes

BACKGROUND & AIMS

Studies have illustrated the role of circadian rhythms in hepatic ischemia/reperfusion injury (HIRI), but the mechanisms are poorly understood. Bmal1 plays a significant role in the circadian control of liver physiology and disease; however, its role in HIRI has not been investigated. Here, we aimed to explore the potential contribution of BMAL1 to HIRI.

METHODS

The impact of ischemia/reperfusion timing (Zeitgeber time [ZT]0 vs. ZT12) on liver damage was assessed in mice with Bmal1 specifically depleted in hepatocytes or myeloid cells. RNA sequencing and other techniques were employed to explore the underlying molecular mechanisms. Additionally, we investigated the role of HSD17B13, a lipid droplet-associated protein, in BMAL1-mediated circadian control of HIRI by utilizing global knockout, hepatocyte-specific knockdown, or hepatocyte-specific humanized HSD17B13 overexpression mouse models.

RESULTS

We found that initiating ischemia/reperfusion operations at ZT12 instead of ZT0 resulted in significantly more severe liver injury in wild-type mice. Bmal1 in hepatocytes, but not in myeloid cells, mediated this temporal difference. Mechanistically, BMAL1 regulates the diurnal oscillation of HIRI by directly controlling Hsd17b13 transcription via binding to E-box-like elements. Hepatocyte-specific knockdown of Hsd17b13 blunted the diurnal variation of HIRI and exacerbated ZT0 HIRI. Furthermore, depletion of the BMAL1/HSD17B13 axis may inhibit lipid degradation by blocking autophagy flux, contributing to lipid overload and exacerbating HIRI. Finally, we demonstrated that hepatocyte-specific overexpression of humanized HSD17B13 may confer protection during ZT0 HIRI but aggravate damage at ZT12.

CONCLUSIONS

Our study uncovers a pivotal role of hepatocyte BMAL1 in modulating circadian rhythms in HIRI via HSD17B13-mediated autophagy and offers a promising strategy for preventing and treating HIRI by targeting the BMAL1/HSD17B13 axis.

IMPACT AND IMPLICATIONS

This study unveils a pivotal role of the BMAL1/HSD17B13 axis in the circadian control of hepatic ischemia/reperfusion injury, providing new insights into the prevention and treatment of hepatic ischemia/reperfusion injury. The findings have scientific implications as they enhance our understanding of the circadian regulation of hepatic ischemia/reperfusion injury. Furthermore, clinically, this research offers opportunities for optimizing treatment strategies in hepatic ischemia/reperfusion injury by considering the timing of therapeutic interventions.

The circadian rhythm: A new target of natural products that can protect against diseases of the metabolic system, cardiovascular system, and nervous system

BACKGROUND

The treatment of metabolic system, cardiovascular system, and nervous system diseases remains to be explored. In the internal environment of organisms, the metabolism of substances such as carbohydrates, lipids and proteins (including biohormones and enzymes) exhibit a certain circadian rhythm to maintain the energy supply and material cycle needed for the normal activities of organisms. As a key factor for the health of organisms, the circadian rhythm can be disrupted by pathological conditions, and this disruption accelerates the progression of diseases and results in a vicious cycle. The current treatments targeting the circadian rhythm for the treatment of metabolic system, cardiovascular system, and nervous system diseases have certain limitations, and the identification of safer and more effective circadian rhythm regulators is needed.

AIM OF THE REVIEW

To systematically assess the possibility of using the biological clock as a natural product target for disease intervention, this work reviews a range of evidence on the potential effectiveness of natural products targeting the circadian rhythm to protect against diseases of the metabolic system, cardiovascular system, and nervous system. This manuscript focuses on how natural products restore normal function by affecting the amplitude of the expression of circadian factors, sleep/wake cycles and the structure of the gut microbiota.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

This work proposes that the circadian rhythm, which is regulated by the amplitude of the expression of circadian rhythm-related factors and the sleep/wake cycle, is crucial for diseases of the metabolic system, cardiovascular system and nervous system and is a new target for slowing the progression of diseases through the use of natural products. This manuscript provides a reference for the molecular modeling of natural products that target the circadian rhythm and provides a new perspective for the time-targeted action of drugs.

Hydroxylation of dihydromyricetin via Beauveria bassiana fermentation enhances its efficacy in improving insulin signaling: Insights into inflammation, oxidative stress, and endoplasmic reticulum stress

Chronic metabolic diseases, particularly insulin resistance (IR) and diabetes, pose significant global health challenges. This study introduces a novel hydroxylated dihydromyricetin (DHM) derivative, 8-hydroxy-DHM (H-DHM), produced via microbial fermentation using Beauveria bassiana. Notably, hydroxylation significantly enhances the efficacy of DHM in glucose consumption, glycogen synthesis, and glucose transport, while inhibiting gluconeogenesis in an IR-HepG2 cell model. This indicates that hydroxylation of DHM can enhance its regulation of glucose metabolism. Mechanistic investigations reveal that H-DHM regulates the JNK/PI3K/AKT signaling pathway by reducing inflammation, oxidative stress, and endoplasmic reticulum stress. These findings highlight the potential of hydroxylated DHM as a promising candidate for dietary and clinical interventions in IR management. Furthermore, this research provides new insights into the modification of natural flavonoids through microbial fermentation, presenting an innovative strategy for managing and preventing chronic metabolic diseases.

Multiple effects of spicy flavors on neurological diseases through the intervention of TRPV1: a critical review

The spicy properties of foods are contributed by various spicy flavor substances (SFs) such as capsaicin, piperine, and allicin. Beyond their distinctive sensory characteristics, SFs also influence health conditions and numerous studies have associated spicy flavors with disease treatment. In this review, we enumerate different types of SFs and describe their role in food processing, with a specific emphasis on critically examining their influence on human wellness. Particularly, detailed insights into the mechanisms through which SFs enhance physiological balance and alleviate neurological diseases are provided, and a systematic analysis of the significance of transient receptor potential vanilloid type-1 (TRPV1) in regulating metabolism and nervous system homeostasis is presented. Moreover, enhancing the accessibility and utilization of SFs can potentially amplify the physiological effects. This review aims to provide compelling evidence for the integration of food flavor and human health.