Aging, Melatonin, and the Pro- and Anti-Inflammatory Networks

Area of Science:

• Aging and immunology
• Circadian biology
• Molecular mechanisms of inflammation

Background:

• Aging is linked to reduced melatonin, immune dysfunction, circadian disruption, and lower sirtuin-1 (SIRT1) activity.
• Melatonin's immune effects are partly mediated by SIRT1 in non-tumor cells.
• Melatonin's role in inflammation is context-dependent, acting as both pro- and anti-inflammatory.

Purpose of the Study:

• To elucidate the multifaceted role of melatonin in regulating inflammatory processes.
• To explore the interplay between melatonin, sirtuin-1 (SIRT1), and immune cell polarization.
• To understand melatonin's influence on key inflammatory pathways and microRNA regulation.

Main Methods:

• Review and synthesis of existing literature on melatonin, SIRT1, and inflammation.
• Analysis of melatonin's effects on pro-inflammatory mediators (e.g., cytokines, NO, NLRP3 inflammasome).
• Examination of melatonin's impact on anti-inflammatory pathways (e.g., Nrf2, NF-κB, IL-4, IL-10) and M2 macrophage polarization.

Main Results:

• Melatonin can suppress various pro-inflammatory processes, including SASP and amyloid-β toxicity.
• Melatonin activates anti-inflammatory networks involving SIRT1, Nrf2, and IL-10.
• Melatonin promotes M2 polarization of macrophages/microglia, favoring anti-inflammatory responses.
• MicroRNAs significantly regulate both pro- and anti-inflammatory networks influenced by melatonin.

Conclusions:

• Melatonin exhibits complex, context-dependent immunomodulatory effects, often acting anti-inflammatorily via SIRT1.
• Melatonin's ability to suppress senescence-associated secretory phenotype and promote M2 polarization is crucial for combating age-related inflammation.
• Understanding melatonin's regulatory interactions with SIRT1 and microRNAs offers therapeutic potential for age-related diseases.