This comprehensive review explores the pivotal role of microRNAs (miRNAs) in cellular regulation, focusing on their biogenesis, mechanisms of action, and implications in various inflammatory and autoimmune diseases. MiRNAs, small non-coding RNAs, play a crucial role in modulating gene expression and cellular processes, influencing both mRNA translation and transcriptional regulation. The review highlights the complex biogenesis of miRNAs, involving transcription, processing, and integration into the RNA-induced silencing complex (RISC). In the cytoplasm, mature miRNAs fine-tune cellular functions by targeting specific mRNAs, while their presence in the nucleus affects transcriptional regulation and epigenetic modifications. The dysregulation of miRNA expression is evident in various pathologies, including cancer, autoimmune diseases, and inflammatory conditions. Epigenetic factors such as DNA methylation and histone modifications significantly influence miRNA abundance and function. The review discusses the multifaceted roles of miRNAs, emphasizing their adaptability to environmental signals and interactions with transcription factors. Mechanisms like competition with RNA-binding proteins, sponging, and control of miRNA levels through degradation and editing contribute to the complexity of miRNA-mediated regulatory networks. The review also delves into the specific impact of miRNA dysregulation in skin-related autoimmune and autoinflammatory diseases, arthritis, cardiovascular diseases, inflammatory bowel diseases, and neurodegenerative disorders. Examples include systemic sclerosis, psoriasis, vitiligo, rheumatoid arthritis, osteoarthritis, atherosclerosis, Crohn's disease, systemic lupus erythematosus, Behçet syndrome, tumor necrosis factor receptor-associated periodic syndrome, and multiple sclerosis. These diseases showcase the dynamic regulation of miRNAs and their potential as diagnostic markers and therapeutic targets. The authors emphasize the importance of continued research to unravel the complexities of miRNA functions, which hold promise for advancing therapeutic interventions and enhancing our understanding of cellular dynamics in health and disease.This comprehensive review explores the pivotal role of microRNAs (miRNAs) in cellular regulation, focusing on their biogenesis, mechanisms of action, and implications in various inflammatory and autoimmune diseases. MiRNAs, small non-coding RNAs, play a crucial role in modulating gene expression and cellular processes, influencing both mRNA translation and transcriptional regulation. The review highlights the complex biogenesis of miRNAs, involving transcription, processing, and integration into the RNA-induced silencing complex (RISC). In the cytoplasm, mature miRNAs fine-tune cellular functions by targeting specific mRNAs, while their presence in the nucleus affects transcriptional regulation and epigenetic modifications. The dysregulation of miRNA expression is evident in various pathologies, including cancer, autoimmune diseases, and inflammatory conditions. Epigenetic factors such as DNA methylation and histone modifications significantly influence miRNA abundance and function. The review discusses the multifaceted roles of miRNAs, emphasizing their adaptability to environmental signals and interactions with transcription factors. Mechanisms like competition with RNA-binding proteins, sponging, and control of miRNA levels through degradation and editing contribute to the complexity of miRNA-mediated regulatory networks. The review also delves into the specific impact of miRNA dysregulation in skin-related autoimmune and autoinflammatory diseases, arthritis, cardiovascular diseases, inflammatory bowel diseases, and neurodegenerative disorders. Examples include systemic sclerosis, psoriasis, vitiligo, rheumatoid arthritis, osteoarthritis, atherosclerosis, Crohn's disease, systemic lupus erythematosus, Behçet syndrome, tumor necrosis factor receptor-associated periodic syndrome, and multiple sclerosis. These diseases showcase the dynamic regulation of miRNAs and their potential as diagnostic markers and therapeutic targets. The authors emphasize the importance of continued research to unravel the complexities of miRNA functions, which hold promise for advancing therapeutic interventions and enhancing our understanding of cellular dynamics in health and disease.