Cyclo(his-pro) TFA (Cyclo(histidyl-proline) TFA) is an orally active cyclic dipeptide structurally related to tyreotropin-releasing hormone[1]. Cyclo(his-pro) TFA could inhibit NF-κB nuclear accumulation. Cyclo(his-pro) TFA can cross the brain-blood-barrier and affect diverse inflammatory and stress responses[2].
Cyclo(his-pro) TFA (Cyclo(histidyl-proline) TFA; 50 μM; 1-48 hours) increases the nuclear level of Nrf2 and inhibits NF-κB nuclear translocation. Cyclo(His-Pro) alone has no effect on nuclear translocation of these transcription factors[2]. Cyclo(his-pro) TFA (50 μM; prior to PQ exposure for 48 hours) abolishes protein nitration that followed paraquat (PQ) exposure and lessenes its functional consequences, as shown by decrease in cell apoptosis, detected by caspase 3 activity and by cytochrome c release[2]. Cyclo(his-pro) TFA inhibits NF-κB nuclear accumulation induced by paraquat in rat pheochromocytoma PC12 cells via the Nrf2/heme oxygenase-1 pathway[2]. Western Blot Analysis[1] Cell Line: PC12 cells
Cyclo(his-pro) TFA (Cyclo(histidyl-proline) TFA; 1.8 mg/ear; topical application on the right ear; 30 min prior to TPA) reduces TPA-induced ear oedema confirming that it can exert anti-inflammatory effect[2]. Cyclo(his-pro) TFA exerts in vivo anti-inflammatory effects in the central nervous system by down-regulating hepatic and cerebral TNFα expression thereby counteracting LPS-induced gliosis. Moreover, by up-regulating Bip, Cyclo(his-pro) increases the ER stress sensitivity andtriggers the unfolded protein response to alleviate the ER stress[3]. Animal Model: Sixty two/three month-old male C57BL/6 mice (25-30 g) [2]
[1]. Grottelli S, et al. The Role of Cyclo(His-Pro) in Neurodegeneration. Int J Mol Sci. 2016 Aug 12;17(8). pii: E1332. [2]. Minelli A, et al. Cyclo(His-Pro) exerts anti-inflammatory effects by modulating NF-κB and Nrf2 signalling. Int J Biochem Cell Biol. 2012 Mar;44(3):525-35. [3]. Bellezza I, et al. Neuroinflammation and endoplasmic reticulum stress are coregulated by cyclo(His-Pro) to prevent LPS neurotoxicity. Int J Biochem Cell Biol. 2014 Jun;51:159-69.