Primary sensory neuron-derived miR-let-7b underlies stress-elicited psoriasis.

Researchers have discovered a fascinating connection between stress and psoriasis flare-ups that may help explain why acupuncture benefits some patients with this chronic skin condition. Scientists studying mice found that chronic stress causes sensory nerve cells in the dorsal root ganglia (clusters of nerve cells along the spine) to release a specific molecule called miR-let-7b into the skin. This molecule then activates immune cells called macrophages, triggering them to release inflammatory chemicals that worsen psoriasis symptoms including scaling, thickening, itching, and inflammation.

In the study, stressed mice developed significantly more severe psoriasis-like symptoms compared to unstressed mice. When researchers blocked the release of miR-let-7b from nerve cells, they could prevent stress from worsening the condition. This discovery reveals a direct pathway connecting the nervous system to immune system activation in psoriasis.

For patients considering acupuncture, this research provides scientific support for why stress-reduction approaches may help manage psoriasis. Acupuncture has traditionally been used to calm the nervous system and reduce stress responses. By potentially modulating nerve cell activity and reducing stress-related inflammation, acupuncture may help interrupt the pathway this study identified. The research suggests that therapies targeting the nervous system's response to stress could complement conventional psoriasis treatments.

While this study was conducted in animals and human trials are needed, it offers a plausible mechanism for how acupuncture's stress-reducing and neuromodulatory effects might benefit psoriasis patients. The findings emphasize the importance of addressing both physical symptoms and stress management in comprehensive psoriasis care. Patients interested in exploring acupuncture for psoriasis should seek treatment from a licensed acupuncturist with experience in dermatological conditions.

This study elucidates a neuroimmune mechanism underlying stress-induced psoriasis exacerbation with implications for acupuncture practice. Using a chronic social defeat stress (CSDS) model combined with imiquimod-induced psoriasis in mice, researchers demonstrated that stress significantly worsens psoriatic symptoms including epidermal scaling, hyperplasia, and inflammation. Mechanistically, CSDS upregulates release of miR-let-7b from dorsal root ganglia (DRG) neuron peripheral terminals into skin tissue. This microRNA acts as an endogenous Toll-like receptor 7 (TLR7) ligand, activating skin-resident macrophages to secrete inflammatory cytokines (IL-6, TNF-α) and chemokines (MCP-1), amplifying immune cell recruitment. Specific blockade of miR-let-7b in DRG neurons prevented stress-induced psoriasis worsening, while intradermal synthetic miR-let-7b injection induced psoriasis-like phenotype in wild-type mice, reversible with TLR7 antagonists. Microfluidic coculture confirmed direct neuron-to-macrophage signaling via the miR-let-7b/TLR7 pathway. Clinical relevance: This identifies DRG neurons as therapeutic targets, supporting acupuncture's potential to modulate peripheral sensory neuron activity and mitigate stress-mediated inflammatory cascades in psoriasis management.