M1 polarization of macrophages promotes stress-induced hair loss via interleukin-18 and interleukin-1ß.

Stress-induced hair loss is a prevalent health concern, with mechanisms that remain unclear, and effective treatment options are not yet available. In this study, we investigated whether stress-induced hair loss was related to an imbalanced immune microenvironment. Screening the skin-infiltrated immune cells in a stressed mouse model, we discovered a significant increase in macrophages upon stress induction. Clearance of macrophages rescues mice from stress-induced hair shedding and depletion of hair follicle stem cells (HFSCs) in the skin, demonstrating the role of macrophages in triggering hair loss in response to stress. Further flow cytometry analysis revealed a significant increase in M1 phenotype macrophages in mice under stressed conditions. In searching for humoral factors mediating stress-induced macrophage polarization, we found that the hormone Norepinephrine (NE) was elevated in the blood of stressed mice. In addition, in-vivo and in-vitro studies confirm that NE can induce macrophage polarization toward M1 through the ß-adrenergic receptor, Adrb2. Transcriptome, enzyme-linked immunosorbent assay (ELISA), and western blot analyses reveal that the NLRP3/caspase-1 inflammasome signaling and its downstream effector interleukin 18 (IL-18) and interleukin 1 beta (IL-1ß) were significantly upregulated in the NE-treated macrophages. However, inhibition of the NE receptor Adrb2 with ICI118551 reversed the upregulation of NLRP3/caspase-1, IL-18, and IL-1ß. Indeed, IL-18 and IL-1ß treatments lead to apoptosis of HFSCs. More importantly, blocking IL-18 and IL-1ß signals reversed HFSCs depletion in skin organoid models and attenuated stress-induced hair shedding in mice. Taken together, this study demonstrates the role of the neural (stress)-endocrine (NE)-immune (M1 macrophages) axis in stress-induced hair shedding and suggestes that IL-18 or IL-1ß may be promising therapeutic targets.

Nrf2 silencing amplifies DNA photooxidative damage to activate the STING pathway for synergistic tumor immunotherapy.

Photodynamic therapy (PDT)-mediated antitumor immune response depends on oxidative stress intensity and subsequent immunogenic cell death (ICD) in tumor cells, yet the inherent antioxidant system restricts reactive oxygen species (ROS)-associated oxidative damage, which is highly correlated with the upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) and the downstream products, such as glutathione (GSH). Herein, to overcome this dilemma, we designed a versatile nanoadjuvant (RI@Z-P) to enhance the sensitivity of tumor cells to oxidative stress via Nrf2-specific small interfering RNA (siNrf2). The constructed RI@Z-P could significantly amplify photooxidative stress and achieve robust DNA oxidative damage, activating the stimulator of interferon genes (STING)-dependent immune-sensing to produce interferon-ß (IFN-ß). Additionally, RI@Z-P together with laser irradiation reinforced tumor immunogenicity by exposing or releasing damage-associated molecular patterns (DAMPs), showing the prominent adjuvant effect for promoting dendritic cell (DC) maturation and T-lymphocyte activation and even alleviating the immunosuppressive microenvironment to some extent.

Natural product rhynchophylline prevents stress-induced hair graying by preserving melanocyte stem cells via the ß2 adrenergic pathway suppression.

Norepinephrine (NA), a stress hormone, can accelerate hair graying by binding to ß2 adrenergic receptors (ß2AR) on melanocyte stem cells (McSCs). From this, NA-ß2AR axis could be a potential target for preventing the stress effect. However, identifying selective blockers for ß2AR has been a key challenge. Therefore, in this study, advanced computer-aided drug design (CADD) techniques were harnessed to screen natural molecules, leading to the discovery of rhynchophylline as a promising compound. Rhynchophylline exhibited strong and stable binding within the active site of ß2AR, as verified by molecular docking and dynamic simulation assays. When administered to cells, rhynchophylline effectively inhibited NA-ß2AR signaling. This intervention resulted in a significant reduction of hair graying in a stress-induced mouse model, from 28.5% to 8.2%. To gain a deeper understanding of the underlying mechanisms, transcriptome sequencing was employed, which revealed that NA might disrupt melanogenesis by affecting intracellular calcium balance and promoting cell apoptosis. Importantly, rhynchophylline acted as a potent inhibitor of these downstream pathways. In conclusion, the study demonstrated that rhynchophylline has the potential to mitigate the negative impact of NA on melanogenesis by targeting ß2AR, thus offering a promising solution for preventing stress-induced hair graying.

PTEN-mediated AKT/ß-catenin signaling enhances the proliferation and expansion of Lgr5+ hepatocytes.

Rationale: Compelling evidence suggests that Lgr5+ hepatocytes repair liver damage by promoting the regeneration of hepatocytes and ductal cells in the case of liver injury. The PTEN-mediated AKT/ß-catenin signaling plays a key role in the regulation of innate immune regulation in the liver. However, the signaling pathways that control Lgr5+ hepatocyte proliferation in the liver remain unclear. Methods: In order to assess the involvement of PTEN-mediated AKT/ß-catenin signaling in the expansion of Lgr5+ hepatocytes upon liver injuries, the Lgr5-CreER; Rosa-mTmG lineage tracing system was used to target Lgr5+ hepatocytes. Results: The tracing of Lgr5+ hepatocytes showed that PTEN deletion and ß-catenin activation significantly promoted the proliferation of Lgr5+ hepatocytes. In converse, the simultaneous inhibition of PTEN and ß-catenin limited Lgr5+ hepatocyte proliferation in the liver. Our findings provide an insight into understanding how PTEN-mediated AKT/ß-catenin signaling regulates the proliferation of Lgr5+ hepatocytes. Conclusion: The outcomes can improve the application potential of Lgr5+ hepatocytes in the treatment of liver injury diseases and provide a new treatment option for liver cancer.

Novel sinomenine derivative 1032 improves immune suppression in experimental autoimmune encephalomyelitis.

Sinomenine (SIN) is an alkaloid isolated from the Chinese medicinal plant Sinomenium acutum. It is widely used as an immunosuppressive drug for treating autoimmune diseases. Due to its poor efficiency, the large-dose treatment presents some side effects and limits its further applications. In this study, we used chemical modification to improve the therapeutic effect of SIN in vitro and in vivo. A new derivative of sinomenine, named 1032, demonstrates significantly improved immunosuppressive activity over that of its parent natural compound (SIN). In an experimental autoimmune encephalomyelitis (EAE) model, 1032 significantly reduced encephalitogenic T cell responses and induced amelioration of EAE, which outcome was related to its selective inhibitory effect on the production of IL-17. By contrast, SIN treatment only led to a moderate alleviation of EAE severity and the expression level of IL-17 was not significantly reduced. Furthermore, 1032 exhibited suppression of Th17, but not Treg, cell differentiation, a result probably related to its inhibitory effect on IkappaB-alpha degradation as well as on IL-6 and TNF-alpha secretion in BMDCs. We speculate that 1032 as a novel anti-inflammatory agent may target DC to block IL-6 production, which in turn would terminate Th17 cell development. Thus, SIN derivative 1032 presents considerable potential in new drug development for treating autoimmune and inflammatory disease.

Negative regulation of virus-triggered IFN-beta signaling pathway by alternative splicing of TBK1.

Induction of Type I IFNs is a central event in antiviral responses and must be tightly controlled. The protein kinase TBK1 is critically involved in virus-triggered type I IFN signaling. In this study, we identify an alternatively spliced isoform of TBK1, termed TBK1s, which lacks exons 3-6. Upon Sendai virus (SeV) infection, TBK1s is induced in both human and mouse cells and binds to RIG-1, disrupting the interaction between RIG-I and VISA. Consistent with that result, overexpression of TBK1s inhibits IRF3 nuclear translocation and leads to a shutdown of SeV-triggered IFN-beta production. Taken together, our data indicate that TBK1s plays an inhibitory role in virus-triggered IFN-beta signaling pathways.