KLF4 and obesity due to melanocortin 4 receptor deficiency: The miR-34a released from adipose tissue exosomes inhibits polarization to M2 macrophages possibly by repressing the expression of KLF4 (Krueppel-like factor 4), a transcription factor involved in stem cell differentiation plasticity, thereby promoting fat tissue-induced inflammation in obesity, and the researchers found that miR-34a expression increases proportionally with the development of diet-induced obesity [25].