Controlled Delivery of T-box21 Small Interfering RNA Ameliorates Autoimmune Alopecia (Alopecia Areata) in a C3H/HeJ Mouse Model

Motonobu Nakamura^*, Jun-ichiro Jo, Yasuhiko Tabata and Osamu Ishikawa^*

From the Department of Dermatology,^*Gunma University, Maebashi; the Department of Dermatology,Kyoto University, Kyoto; and the Department of Biomaterials,Field of Tissue Engineering, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan

Autoimmune alopecia (alopecia areata) is considered to be triggeredby a collapse of immune privilege in hair follicles. Here weconfirmed that infiltrating CD4 T lymphocytes around hair folliclesof patients with alopecia areata were primarily CCR5-positivewith few CCR4-positive cells, suggesting a dominant role ofTh1 cells in the alopecic lesion. Given this finding, we soughtto elucidate the effect of cytokine therapy in C3H/HeJ mice,a mouse model of alopecia areata, by applying recombinant interleukin-4and neutralizing anti-interferon- ${gamma}$ antibody. We found that localinjections of both interleukin-4 and neutralizing anti-interferon- ${gamma}$ antibody effectively treated alopecia in C3H/HeJ mice. Resultsfrom immunohistochemistry and semiquantitative reverse transcription-polymerasechain reaction demonstrated that intralesional injection ofinterleukin-4 suppressed CD8 T cell infiltrates around the hairfollicles and repressed enhanced interferon- ${gamma}$ mRNA expressionin the affected alopecic skin. Furthermore, Th1 transcriptionfactor T-box21 small interfering RNAs conjugated to cationizedgelatin showed mitigating effects on alopecia in C3H/HeJ mice,resulting in the restoration of hair shaft elongation. Takentogether, the use of gelatin–small interfering RNA conjugatespromises to be a novel, efficient, and safe tool as an alternativegene therapy for the treatment of various human diseases. Toour knowledge, this is the first report of effective controlleddelivery of small interfering RNA using biodegradable cationizedgelatin microspheres in an animal model of disease.