Skin-resident Langerhans cells drive neuropathic pain via chemokine-dependent neuron-immune communication
Paola Pacifico, Dale George, Nirupa D. Jayaraj, Dongjun Ren, James S. Coy-Dibley, Abdelhak A. Belmadani, Sofia Veronesi, Mirna Andelic, Daniele Cartelli, Grazia Devigili, Raffaella Lombardi, Giuseppe Lauria Pinter, Amy S. Paller, Richard J. Miller, Daniela M. Menichella
Paola Pacifico, Dale George, Nirupa D. Jayaraj, Dongjun Ren, James S. Coy-Dibley, Abdelhak A. Belmadani, Sofia Veronesi, Mirna Andelic, Daniele Cartelli, Grazia Devigili, Raffaella Lombardi, Giuseppe Lauria Pinter, Amy S. Paller, Richard J. Miller, Daniela M. Menichella
View: Text | PDF
Research Article Dermatology Immunology Neuroscience

Skin-resident Langerhans cells drive neuropathic pain via chemokine-dependent neuron-immune communication

Abstract

Neuropathic pain affects over 20 million people in the United States, and painful diabetic neuropathy (PDN), a common complication of diabetes, is among its most prevalent and treatment-resistant forms. Although PDN is characterized by nociceptor dysfunction, the upstream peripheral mechanisms remain incompletely understood. While dorsal root ganglion (DRG) nociceptor hyperexcitability is a hallmark of PDN, emerging evidence suggests that nonneuronal skin cells may modulate nociceptor function. Here, we investigated whether epidermal Langerhans cells (LCs) contribute to neuropathic pain in PDN through neuroimmune signaling. Using a clinically relevant high-fat diet (HFD) mouse model, transgenic LC ablation, behavioral assays, human skin biopsies, and single-cell RNA seq of epidermis and DRG, we found that LC density increased in male diabetic mice in parallel with mechanical allodynia. In skin samples of people with PDN, LCs exhibited increased volume and dendritic complexity correlating with diabetes duration. Genetic depletion of LCs prevented mechanical allodynia and spontaneous pain-like behavior in male, but not female, HFD mice, revealing a sex-dependent contribution. Single-cell and interactome analyses identified male-specific inflammatory LC programs, including upregulation of chemokine signaling pathways. Consistently, LC secretome profiling showed increased CCL2 release, and local CCR2 blockade reversed allodynia. These findings identify epidermal LCs as peripheral regulators of PDN pain and highlight sex-dependent chemokine-mediated neuron-immune communication at the skin-nerve interface.

Authors

Paola Pacifico, Dale George, Nirupa D. Jayaraj, Dongjun Ren, James S. Coy-Dibley, Abdelhak A. Belmadani, Sofia Veronesi, Mirna Andelic, Daniele Cartelli, Grazia Devigili, Raffaella Lombardi, Giuseppe Lauria Pinter, Amy S. Paller, Richard J. Miller, Daniela M. Menichella

×

Figure 1

Increased LC density in HFD male mice.

Options: View larger image (or click on image) Download as PowerPoint
Increased LC density in HFD male mice. (A and B) Quantification of LC de...
(A and B) Quantification of LC density (number of LCs/mm2) in RD and HFD male mice at 10 weeks (10w) (A) and representative images (B). n = 4 animals for RD and n = 5 animals for HFD. n = 3 sections per animal were acquired and CD207+ cells per 0.04 mm2 per section area were counted. Unpaired 2-tailed t test with Welch’s correction *P = 0.0176. (C) MACSQuant Tyto cell sorting of CD207+/CD45+ gated cells from single cells paw epidermis suspension. PE-CD207 and APC-CD45 antibodies were used to colabel LCs. (D) Graph shows the average percentage from 3 replicates of CD207+/CD45+-sorted cells in RD and HFD. Unpaired 2-tailed t test **P = 0.0010. n = 4 animals per diet condition per each replicate. (E) Time-course experiment of LC density at 2, 4, 6, 8, and 10w show the progressive increase of LC in HFD. Phenotypic characterization of HFD mice at 2, 4, 6, 8, and 10w obtained from published data (38). Two-way ANOVA for multiple comparisons. Between RD and HFD: 8w *P = 0.0216. 10w **P = 0.0014. Within HFD: 2w versus 10w P = 0.0111; 4w versus 10w P = 0.0116; 6w versus 10w P = 0.0486; 8w versus 10w P = 0.0469. 2w: n = 3 animals for both RD and HFD. 4w: n = 3 animals for both RD and HFD. 6w: n = 3 animals for RD and n = 4 for HFD. 8w: n = 4 animals for RD and n = 3 for HFD. 10w: n = 4 animals for RD and n = 3 for HFD. (F) Representative images of LCs CD207+ in epidermal sheets of RD and HFD mice at different time points. (G) Correlation matrix of HFD male features at different time points (2, 4, 6, 8, 10w) including Glucose Tolerance Test (GTT), mechanical allodynia (vonFrey) and LC density. Red squares indicate negative correlations. 10w vonFrey-LCs: Pearson r = –0.9199, P = 0.003. (H) Negative correlation between LC density and mechanical threshold measured with vonFrey test in 10w HFD mice. Pearson r coefficient –0.9199; r2 = 0.8462; P = 0.0033.