A genetically modified mesenchymal stem cell (MSC) includes an exogenous nucleic acid that includes a Klotho encoding region operably linked to a promoter or promoter/enhancer combination. The MSCs can be used for the treatment of cancer, organ fibrosis, renal failure, age-related changes of organs or organ systems, arteriosclerosis, and neurodegenerative diseases, such as Alzheimer's disease (AD), Multiple sclerosis (MS), Huntington's disease, Amyotrophic Lateral Sclerosis (ALS), Parkinson's disease, and Schizophrenia, as well as dementia, diabetes mellitus, sepsis and autoimmune diseases and autoimmune-related diseases.