Induction of Fibroblast-to-Myofibroblast Differentiation by Changing Cytoplasmic Actin Ratio

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Yulia G. Levuschkina^1,2#, Vera B. Dugina^1,2#, Galina S. Shagieva¹, Sergey V. Boichuk^3,4, Ilya I. Eremin⁵, Natalia V. Khromova⁶, Pavel B. Kopnin^6,a*

¹Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia

²Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia

³Department of Pathology, Kazan State Medical University, 420012 Moscow, Russia

⁴Department of Radiotherapy and Radiology, Russian Medical Academy of Continuous Professional Education, 119454 Moscow, Russia

⁵Petrovsky National Research Center of Surgery, 119991 Moscow, Russia

⁶Scientific Research Institute of Carcinogenesis, N. N. Blokhin National Medical Research Center of Oncology, 115478 Moscow, Russia

^* To whom correspondence should be addressed.

^# These authors contributed equally to the work.

Received: November 19, 2024; Revised: January 9, 2025; Accepted: January 14, 2025

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Myofibroblasts, which play a crucial role in the tumour microenvironment, represent a promising avenue for research in the field of oncotherapy. This study investigates the potential for the induced differentiation of human fibroblasts into myofibroblasts through downregulation of the γ-cytoplasmic actin (γ-CYA) achieved by RNA interference. A decrease in the γ-CYA expression in human subcutaneous fibroblasts resulted in upregulation of myofibroblast markers, including α-smooth muscle actin (α-SMA), ED-A FN, and type III collagen. These changes were accompanied by notable alterations in cellular morphology, characterized by a significant increase in cell area and the formation of pronounced supermature focal adhesions. Downregulation of γ-CYA resulted in the compensatory increase in expression of the β-cytoplasmic actin and α-SMA, and formation of the characteristic α-SMA-positive stress fibers. In conclusion, our results demonstrate that a decrease in the γ-CYA expression leads to myofibroblastic trans-differentiation of human subcutaneous fibroblasts.

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KEY WORDS: actin isoforms, fibroblasts, myofibroblasts, stromal microenvironment, differentiation

DOI: 10.1134/S000629792460412X

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