BDNF and diabetes mellitus: A close association between HFD-induced diabetes and obesity activated the transcription factor cytosine-cytosine-adenosine-adenosine-thymidine (CCAAT)/enhancer binding protein β (C/EBPβ) in hippocampal neurons, which repressed BDNF expression and caused depression-like behavior has been frequently suggested (Li et al., 2022).