Repurposing the anti-pulmonary hypertensive drug into a longevity-promoting drug: Sitaxentan (trade name: Thelin), an anti-pulmonary hypertensive drug, increases NMN/NAD levels, decreases interaction of DBC1 with PARP1, increases PARP1 activity, promotes DNA repair, augments tolerance against radiation, cancer, and aging, via down-regulation of its target gene, 28/October/2018, 1.55 pm