Comprehensive Analysis of the Influences and Regulatory Mechanisms of Circadian Rhythm Genes on Multiple Human Tissues and Organs

The circadian rhythm is an endogenous, approximately 24-hour cycle serving as the fundamental regulatory mechanism within organisms. The suprachiasmatic nucleus (SCN) of the hypothalamus acts as the central pacemaker, integrating inputs from rhythmic gene expression, melanopsin-expressing retinal ganglion cells (ipRGCs) sensitive to blue light, and other cues to precisely orchestrate diverse physiological functions. This master regulator governs gene expression profiles, neuroendocrine signaling, and multiple pathways to modulate vital activities including heart rate, respiration, and hormone secretion. It maintains rhythmic stability in critical processes such as brain waste clearance (e.g., glymphatic system function) and dopamine synthesis. Genetic disruption of core clock components is implicated in the pathogenesis of major depressive disorder (MDD). Within the cardiovascular system, core clock genes such as CLOCK and BMAL1 (forming a heterodimeric transcription factor) drive the characteristic "higher daytime, lower nighttime" rhythm in myocardial contractility, blood pressure, and related functions, thereby preserving cardiac structure and function. Circadian disruption exacerbates the risk for hypertension (HTN) and heart failure (HF). Concurrently, circadian genes regulate the maturation, localization, and effector functions of immune cells, including macrophages and lymphocytes. Disruption predisposes individuals to chronic inflammation and immune deficiency, and negatively impacts therapeutic efficacy in diseases like cancer. Furthermore, the circadian system interfaces with endocrine and metabolic systems, influencing healthspan and longevity. It is intrinsically linked to homeostatic sleep drive and conditions like pandemic-related circadian rhythm sleep-wake disorders. Acting as the key "invisible sentinel" of organismal homeostasis, circadian rhythm disruption significantly elevates the risk profile for a broad spectrum of pathologies.