Involucrin, But Not Filaggrin and Kdap mRNA, Expression Is Downregulated in 3-D Cultures of Intact Rat Hair Bulbs After Calcium Stimulation

The study investigated the effect of calcium on the expression of differentiation markers in rat hair follicles, specifically focusing on the hair bulb region. Researchers found that while increased calcium levels upregulated the expression of involucrin, filaggrin, trichohyalin, and keratinocyte differentiation associated protein (Kdap) in cultures of cells derived from hair bulbs, the intact hair bulbs themselves showed a downregulation of involucrin and trichohyalin expression. This suggests that the inner root sheath (IRS) has an inhibitory effect on the expression of certain differentiation markers within the hair bulb. The study concluded that the downregulation of involucrin under the influence of calcium occurs in both the hair bulb and mid-segments of the hair follicle, indicating that separating these parts may not be necessary for future experiments. The number of hair follicles or the number of experiments conducted was not specified in the summary provided.