Berberine inhibits palmitate-induced NLRP3 inflammasome activation by triggering autophagy in macrophages: A new mechanism linking berberine to insulin resistance improvement.

NLRP3 (Nod-like receptor family pyrin domain containing 3) inflammasome has been reported to contribute to obesity-induced inflammation and insulin resistance. However, there are few drugs targeting NLRP3 inflammasome for the treatment of insulin resistance. In the present study, we showed that berberine (BBR) significantly suppressed saturated fatty acid palmitate (PA)-induced NLRP3 inflammasome activation and interleukin-1β (IL-1β) release in macrophages, which was one of the most important mediators in the insulin sensitivity of adipose tissue. BBR treatment dramatically upregulated macrophage autophagic level while knockdown beclin1 and autophagy inhibitor reversed BBR's suppression on inflammasome. Furthermore, AMPK (adenosine monophosphate-activated protein kinase) inhibitor Adenine 9-β-d-arabinofuranoside (Ara-A) blocked most effects of BBR, suggesting that AMPK signals may be involved in BBR-induced macrophage autophagy. Importantly, BBR also prevented NLRP3 inflammasome-dependent inflammation and metabolic disorder in a high-fat-diet-induced insulin resistance model. Adoptive transfer of BBR-treated bone marrow-derived macrophages (BMDMs), which was induced by lipopolysaccharide (LPS) plus palmitate-bovine serum albumin (PA-BSA), significantly ameliorated insulin resistance of ob/ob mice as compared with control mice. However, the co-treatment of the BMDMs with autophagy inhibitor 3-Methyladenine (3-MA) reversed the effect of BBR almost completely. Taken together, BBR exerted its anti-inflammatory effects through activation of AMPK-dependent autophagy in adipose tissue macrophages (ATMs). This study amplified the mechanisms of BBR and its potential in attenuating insulin resistance.

Zhou H ，Feng L ，Xu F ，Sun Y ，Ma Y ，Zhang X ，Liu H ，Xu G ，Wu X ，Shen Y ，Sun Y ，Wu X ，Xu Q ... -  《-》

Berberine suppresses influenza virus-triggered NLRP3 inflammasome activation in macrophages by inducing mitophagy and decreasing mitochondrial ROS.

Berberine (BBR) is an isoquinoline alkaloid extracted from several commonly used Chinese herbs. Our previous studies demonstrated BBR-mediated alleviation of lung injury due to inflammation and decrease in the mortality of mice with influenza viral pneumonia. The recent argument of autophagy against inflammatory responses has aroused wide concerns. This study focuses on the reactive oxygen species-Nod-like receptor protein 3 (ROS-NLRP3) pathway to investigate whether BBR inhibits NLRP3 inflammasome activation by inducing mitophagy. Our results demonstrate that BBR and mitochondrion-targeted superoxide dismutase mimetic (Mito-TEMPO; a specific mitochondrial ROS scavenger) significantly restricted NLRP3 inflammasome activation, increased mitochondrial membrane potential (MMP), and decreased mitochondrial ROS (mtROS) generation in J774A.1 macrophages infected with PR8 influenza virus. These observations suggest that the inhibitory effects of BBR on NLRP3 inflammasome activation were associated with the amelioration of mtROS generation. BBR treatment induced regular mitophagy, as evident from the increase in microtubule-associated protein 1 light chain 3 II, decrease in p62, colocalization of LC3 and mitochondria, and formation of autophagosomes. However, 3-methyladenine, an autophagy inhibitor, reversed the inhibitory effects of BBR on mitochondrial damage and NLRP3 inflammasome activation in influenza virus-infected macrophages, indicating the involvement of mitophagy in mediating the inhibitory effects of BBR on NLRP3 inflammasome activation. Furthermore, the knockdown of Bcl-2/adenovirus E18-19-kDa interacting protein 3 (BNIP3) expression attenuated the effects of BBR on mitophagy induction to some extent, suggesting that the BBR-induced mitophagy may be, at least in part, mediated in a BNIP3-dependent manner. Similar results were obtained in vivo using a mouse model of influenza viral pneumonia that was administered with BBR. Taken together, these findings suggest that restricting NLRP3 inflammasome activation by decreasing ROS generation through mitophagy induction may be crucial for the BBR-mediated alleviation of influenza virus-induced inflammatory lesions.

Liu H ，You L ，Wu J ，Zhao M ，Guo R ，Zhang H ，Su R ，Mao Q ，Deng D ，Hao Y ... -  《-》

Chikusetsu saponin IVa ameliorates high fat diet-induced inflammation in adipose tissue of mice through inhibition of NLRP3 inflammasome activation and NF-κB signaling.

Yuan C ，Liu C ，Wang T ，He Y ，Zhou Z ，Dun Y ，Zhao H ，Ren D ，Wang J ，Zhang C ，Yuan D ... -  《Oncotarget》

Berberine inhibits NLRP3 inflammasome activation and proinflammatory macrophage M1 polarization to accelerate peripheral nerve regeneration.

Berberine (BBR) has demonstrated potent anti-inflammatory effects by modulating macrophage polarization. Nevertheless, the precise mechanisms through which berberine regulates post-injury inflammation within the peripheral nerve system remain elusive. This study seeks to elucidate the role of BBR and its underlying mechanisms in inflammation following peripheral nerve injury (PNI). Adult male C57BL/6J mice subjected to PNI were administered daily doses of berberine (0, 60, 120, 180, 240 ​mg/kg) via gavage from day 1 through day 28. Evaluation of the sciatic function index (SFI) and paw withdrawal threshold revealed that BBR dose-dependently enhanced both motor and sensory functions. Immunofluorescent staining for anti-myelin basic protein (anti-MBP) and anti-neurofilament-200 (anti-NF-200), along with histological staining comprising hematoxylin-eosin (HE), luxol fast blue (LFB), and Masson staining, demonstrated that BBR dose-dependently promoted structural regeneration. Molecular analyses including qRT-PCR, Western blotting, enzyme-linked immunosorbent assay (ELISA), and immunofluorescence confirmed that inactivation of the NLRP3 inflammasome by MCC950 shifted macrophages from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype, while also impeding macrophage infiltration. Furthermore, BBR significantly downregulated the expression of the NLRP3 inflammasome and its associated molecules in macrophages, thereby mitigating NLRP3 inflammasome activation-induced macrophage M1 polarization and inflammation. In summary, BBR's neuroprotective effects were concomitant with the suppression of inflammation after PNI, achieved through the inhibition of NLRP3 inflammasome activation-induced macrophage M1 polarization.

Sun J ，Zeng Q ，Wu Z ，Huang L ，Sun T ，Ling C ，Zhang B ，Chen C ，Wang H ... -  《-》

NLRP3 inflammasome as a target of berberine in experimental murine liver injury: interference with P2X7 signalling.

Berberine (BRB) is commonly used in herbal medicine, but its mechanisms of action are poorly understood. In the present study, we tested BRB in steatohepatitis induced by a methionine- and choline-deficient (MCD) diet, in acute acetaminophen intoxication and in cultured murine macrophages. BRB markedly improved parameters of liver injury and necroinflammation induced by the MCD diet, although increased mortality was observed by mechanisms independent of bacterial infections or plasma levels of BRB. The MCD diet induced up-regulation of all components of the NLRP3 (NACHT, LRR and PYD domain-containing protein 3) inflammasome, and increased hepatic levels of mature IL-1β (interleukin 1β). All of these parameters were significantly reduced in mice treated with BRB. In mice administered an acetaminophen overdose, a model dependent on inflammasome activation, BRB reduced mortality and ALT (alanine aminotransferase) elevation, and limited the expression of inflammasome components. In vitro, LPS (lipopolysaccharide)-induced activation of NLRP3 inflammasome in RAW264.7 murine macrophages was markedly decreased by pre-incubation with BRB. BRB significantly limited the activation of the purinergic receptor P2X7, involved in the late phases of inflammasome activation. Upon P2X7 knockdown, the ability of BRB to block LPS-induced secretion of IL-1β was lost. These data indicate that administration of BRB ameliorates inflammation and injury in two unrelated murine models of liver damage. We demonstrate for the first time that BRB interferes with activation of the NLRP3 inflammasome pathway in vivo and in vitro, through a mechanism based on interference with activation of P2X7, a purinergic receptor involved in inflammasome activation.

Vivoli E ，Cappon A ，Milani S ，Piombanti B ，Provenzano A ，Novo E ，Masi A ，Navari N ，Narducci R ，Mannaioni G ，Moneti G ，Oliveira CP ，Parola M ，Marra F ... -  《-》