In fact, disruption of the clock components PERs, CLOCK and BMAL1 has been shown to affect regulation of hair follicle bulge stem cell cycling [158], cell-intrinsic keratinocyte differentiation or proliferation responses [159,160,161,162], epidermal wound repair [163], myocardial response to infarction [164], lung response to pro-inflammatory cues [165], hematopoietic system replenishment [166,167], intestinal stem cell renewal and intestinal epithelial regeneration especially after damage from gastrointestinal disease [168,169,170,171]. Here, CLOCK is linked to gastrointestinal disease.