On-off system for PI3-kinase-Akt signaling through S-nitrosylation of phosphatase with sequence homology to tensin (PTEN).

Nitric oxide (NO) physiologically regulates numerous cellular responses through S-nitrosylation of protein cysteine residues. We performed antibody-array screening in conjunction with biotin-switch assays to look for S-nitrosylated proteins. Using this combination of techniques, we found that phosphatase with sequence homology to tensin (PTEN) is selectively S-nitrosylated by low concentrations of NO at a specific cysteine residue (Cys-83). S-nitrosylation of PTEN (forming SNO-PTEN) inhibits enzymatic activity and consequently stimulates the downstream Akt cascade, indicating that Cys-83 is a critical site for redox regulation of PTEN function. In ischemic mouse brain, we observed SNO-PTEN in the core and penumbra regions but found SNO-Akt, which is known to inhibit Akt activity, only in the ischemic core. These findings suggest that low concentrations of NO, as found in the penumbra, preferentially S-nitrosylate PTEN, whereas higher concentrations of NO, known to exist in the ischemic core, also S-nitrosylate Akt. In the penumbra, inhibition of PTEN (but not Akt) activity by S-nitrosylation would be expected to contribute to cell survival by means of enhanced Akt signaling. In contrast, in the ischemic core, SNO-Akt formation would inhibit this neuroprotective pathway. In vitro model systems support this notion. Thus, we identify unique sites of PTEN and Akt regulation by means of S-nitrosylation, resulting in an "on-off" pattern of control of Akt signaling.

Assessing the economics of biologic and small molecule therapies for the treatment of moderate to severe ulcerative colitis in Japan: a cost per responder analysis of upadacitinib.

AIM: Patients with moderately to severely active ulcerative colitis have an increasing number of advanced therapy options including several biologics and Janus kinase inhibitors. Though data on efficacy and safety of these advanced therapies are available, less is known about the potential economic implications of their utilization in Japan. We evaluated the relative value of these advanced therapies in Japan using a locally developed cost per responder model. METHODS: A model was developed using relevant clinical endpoints and treatment costs to calculate cost per responder of all advanced therapies used for moderately to severely active ulcerative colitis treatment in Japan. Cost per responder was assessed in biologic-naïve and biologic-exposed populations, respectively. The model incorporated induction and maintenance therapy pathways as patients progressed through based on efficacy rates (clinical response, clinical remission and endoscopic improvement). Total costs for induction and maintenance included: drug acquisition, drug administration and serious adverse event management (as necessary) for responders, with additional rescue treatment cost only for non-responders. RESULTS: Upadacitinib showed lower cost per clinical response and cost per clinical remission across both biologic-naïve and biologic-exposed populations with only one exemption in cost per clinical remission in biologic-naïve population. In addition, upadacitinib demonstrated lower cost per endoscopic improvement in both populations. Janus kinase inhibitors outperformed with lower cost per responder than other mediations across all outcomes and patient populations with the exception of tofacitinib for clinical remission in biologic-exposed UC population. LIMITATIONS: Comparative data used in this analysis have been derived from network meta-analysis, not from direct comparison. CONCLUSIONS: The results of this cost per responder analysis suggest upadacitinib is a cost-effective option for the first- and second-line treatment of moderately to severely active ulcerative colitis in Japan.