SIRT1 downregulation provokes immune-inflammatory responses in hair follicle outer root sheath cells and may contribute to development of alopecia areata

Modulating immune responses in alopecia: therapeutic insights and potential targets of antisense oligonucleotides

BACKGROUND

Alopecia areata (AA) are hair loss disorders with distinct pathogenetic mechanisms involving immune dysregulation and microRNA modulation. AA, a T cell-mediated autoimmune disease, is characterized by sudden hair loss, with interferon-gamma (IFN-γ) playing a pivotal role in pathogenesis. The upregulation of IFN response genes, including IFN-inducible chemokines CXCL9, CXCL10, and CXCL11, in lesional skin reflects the activation of the IFN response pathway and contributes to immune cell recruitment and inflammation.

RESULTS

Recent research highlights the role of SIRT1, a class III histone deacetylase, in modulating immune responses in AA. SIRT1 inhibition promotes the production of Th1 cytokines and chemokines, impairing inflammation, while SIRT1 activation suppresses autoreactive responses through NF-κB deacetylation and STAT3 phosphorylation. Additionally, antisense oligonucleotides (ASOs) targeting miR-485-3p show therapeutic potential in promoting hair regrowth and mitigating inflammation in murine models of androgenic alopecia (AGA) and AA.

CONCLUSION

Understanding chemokine dysregulation provides key insights into AA pathogenesis and highlights TAMI-M as a potential therapy for reducing inflammation and promoting hair regeneration. These findings advance the exploration of immune, microRNA, and SIRT1 pathways as targets for novel hair loss treatments.

The aqueous extract of Armadillidium vulgare Latreille alleviates neuropathic pain via inhibiting neuron-astrocyte crosstalk mediated by the IL-12-IFN-γ-IFNGR-CXCL10 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Armadillidium vulgare Latreille (AV), the dried body of pillbug, was originally described in Shennong's Classic of Materia Medica. As a common analgesic in animal-based traditional Chinese medicine, it is mainly used to relieve pain, promoting diuresis, relieving fatigue and so on. Our work demonstrated that AV could alleviate various types of acute and chronic pain including neuropathic pain (NP). And transcriptome sequencing analysis revealed that AV could suppress CXCL10 to alleviate NP, however, the upstream mechanisms governing CXCL10 synthesis remain vague.

AIM OF THE STUDY

The research's goal was to identify the mechanism via which AV regulates CXCL10 to ameliorate NP.

MATERIALS AND METHODS

Chronic constriction injury (CCI) to the sciatic nerve was used to induce the NP model 14 days following surgery. To identify cell signaling pathways, various approaches were used, including transcriptome sequencing, western blotting, immunofluorescence, as well as ELISA. The in vitro assay involved the cultivation of neuron PC12 cells and astrocyte C6 cells.

RESULTS

Both in vivo and in vitro results demonstrated that IL-12/IL-18 enhanced IFN-γ production in spinal neurons, which acted on IFN-γ receptors on neurons and astrocytes to upregulate CXCL10 expression in these cells, illustrating the pivotal role of IL-12 in the crosstalk between neurons and astrocytes. The role of IL-12 in pain regulation was elucidated for the first time within the nervous system. Additionally, its synergistic interaction with IL-18 on the downstream IFN-γ-CXCL10 pathway dramatically altered the activation of neurons and astrocytes. And AV could suppress CXCL10 to alleviate NP by mediating the IL-12-IFN-γ-IFNGR signaling pathway.

CONCLUSIONS

We explored a new target for NP by regulating neuron-astrocyte crosstalk and provided a theoretical basis for AV in clinical use.

MiR-128-3p promotes hyperproliferation of keratinocytes and psoriasis-like inflammation by targeting SIRT1/HIF-1α

Psoriasis is a long-lasting inflammatory skin condition characterized by excessive keratinocyte growth. Recent studies have confirmed abnormal regulation of microRNAs (miRNAs/miRs) in individuals with psoriasis. This study aimed to investigate the function and specific mechanism of action of miR-128a-3p in interleukin-22 (IL-22)-stimulated HaCaT cells. The expression level of miR-128-3p and sirtuin 1 (SIRT1)/hypoxia inducible factor (HIF-1α) was detected using qRT-PCR on patients with psoriasis and IL-22-treated HaCaT cell model. Western blotting was used to detect apoptosis-associated proteins and SIRT1/HIFα pathway protein expression levels. The cell viability was determined using the CCK-8 method. Flow cytometry was performed to detect apoptosis following IL-22 stimulation or transfection. Enzyme-linked immunosorbent assay (ELISA) was used to detect cellular inflammatory factor secretion. The relationship between miR-128-3p and SIRT1 was predicted using the Starbase database and verified using a dual-luciferase reporter gene assay. In patients with psoriasis and IL-22-stimulated HaCaT cells, miR-128-3p and HIF-1α expression levels were elevated and SIRT1 expression was decreased. miR-128-3p directly targeted SIRT1. IL-22 stimulation significantly elevated cell viability, inhibited apoptosis levels and cleaved-caspase3 protein expression, and promoted an inflammatory response in HaCaT cells, which was further promoted by the miR-128-3p mimic. The miR-128-3p inhibitor reduced cell viability, promoted cell apoptosis and cleaved-caspase3 protein expression, and inhibited the inflammatory response in IL-22-induced HaCaT cells; these effects were at least partly reversed by SIRT1-siRNA. miR-128-3p expression is elevated in psoriasis and promotes psoriasis progression by inhibiting SIRT1 expression.

Innovative strategies for the discovery of new drugs against alopecia areata: taking aim at the immune system

INTRODUCTION

The autoimmune hair loss condition alopecia areata (AA) exacts a substantial psychological and socioeconomic toll on patients. Biotechnology companies, dermatology clinics, and research institutions are dedicated to understanding AA pathogenesis and developing new therapeutic approaches. Despite recent efforts, many knowledge gaps persist, and multiple treatment development avenues remain unexplored.

AREAS COVERED

This review summarizes key AA disease mechanisms, current therapeutic methods, and emerging treatments, including Janus Kinase (JAK) inhibitors. The authors determine that innovative drug discovery strategies for AA are still needed due to continued unmet medical needs and the limited efficacy of current and emerging therapeutics. For prospective AA treatment developers, the authors identify the pre-clinical disease models available, their advantages, and limitations. Further, they outline treatment development opportunities that remain largely unmapped.

EXPERT OPINION

While recent advancements in AA therapeutics are promising, challenges remain, including the lack of consistent treatment efficacy, long-term use and safety issues, drug costs, and patient compliance. Future drug development research should focus on patient stratification utilizing robust biomarkers of AA disease activity and improved quantification of treatment response. Investigating superior modes of drug application and developing combination therapies may further improve outcomes. Spirited innovation will be needed to advance more effective treatments for AA.

Noval advance of histone modification in inflammatory skin diseases and related treatment methods

Inflammatory skin diseases are a group of diseases caused by the disruption of skin tissue due to immune system disorders. Histone modification plays a pivotal role in the pathogenesis and treatment of chronic inflammatory skin diseases, encompassing a wide range of conditions, including psoriasis, atopic dermatitis, lupus, systemic sclerosis, contact dermatitis, lichen planus, and alopecia areata. Analyzing histone modification as a significant epigenetic regulatory approach holds great promise for advancing our understanding and managing these complex disorders. Additionally, therapeutic interventions targeting histone modifications have emerged as promising strategies for effectively managing inflammatory skin disorders. This comprehensive review provides an overview of the diverse types of histone modification. We discuss the intricate association between histone modification and prevalent chronic inflammatory skin diseases. We also review current and potential therapeutic approaches that revolve around modulating histone modifications. Finally, we investigated the prospects of research on histone modifications in the context of chronic inflammatory skin diseases, paving the way for innovative therapeutic interventions and improved patient outcomes.

Melatonin Exerts Prominent, Differential Epidermal and Dermal Anti-Aging Properties in Aged Human Eyelid Skin Ex Vivo

Human skin aging is associated with functional deterioration on multiple levels of physiology, necessitating the development of effective skin senotherapeutics. The well-tolerated neurohormone melatonin unfolds anti-aging properties in vitro and in vivo, but it remains unclear whether these effects translate to aged human skin ex vivo. We tested this in organ-cultured, full-thickness human eyelid skin (5-6 donors; 49-77 years) by adding melatonin to the culture medium, followed by the assessment of core aging biomarkers via quantitative immunohistochemistry. Over 6 days, 200 µM melatonin significantly downregulated the intraepidermal activity of the aging-promoting mTORC1 pathway (as visualized by reduced S6 phosphorylation) and MMP-1 protein expression in the epidermis compared to vehicle-treated control skin. Conversely, the transmembrane collagen 17A1, a key stem cell niche matrix molecule that declines with aging, and mitochondrial markers (e.g., TFAM, MTCO-1, and VDAC/porin) were significantly upregulated. Interestingly, 100 µM melatonin also significantly increased the epidermal expression of VEGF-A protein, which is required and sufficient for inducing human skin rejuvenation. In aged human dermis, melatonin significantly increased fibrillin-1 protein expression and improved fibrillin structural organization, indicating an improved collagen and elastic fiber network. In contrast, other key aging biomarkers (SIRT-1, lamin-B1, p16INK4, collagen I) remained unchanged. This ex vivo study provides proof of principle that melatonin indeed exerts long-suspected but never conclusively demonstrated and surprisingly differential anti-aging effects in aged human epidermis and dermis.