TCF-1 is a key transcription factor in progenitor exhausted CD8 T cells (Tex). Moreover, this Tex cell subset mediates responses to PD-1 checkpoint pathway blockade. However, the role of the transcription factor TCF-1 in early fate decisions and initial generation of Tex cells is unclear. Single-cell RNA sequencing (scRNA-seq) and lineage tracing identified a TCF-1 + Ly108 + PD-1 + CD8 T cell population that seeds development of mature Tex cells early during chronic infection. TCF-1 mediated the bifurcation between divergent fates, repressing development of terminal KLRG1 Hi effectors while fostering KLRG1 Lo Tex precursor cells, and PD-1 stabilized this TCF-1 + Tex precursor cell pool. TCF-1 mediated a T-bet-to-Eomes transcription factor transition in Tex precursors by promoting Eomes expression and drove c-Myb expression that controlled Bcl-2 and survival. These data define a role for TCF-1 in early-fate-bifurcationdriving Tex precursor cells and also identify PD-1 as a protector of this early TCF-1 subset.

The Yorkie homologues YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif, also known as WWTR1), effectors of the Hippo pathway, have been identified as mediators for mechanical stimuli. However, the role of YAP/TAZ in haemodynamics-induced mechanotransduction and pathogenesis of atherosclerosis remains unclear. Here we show that endothelial YAP/TAZ activity is regulated by different patterns of blood flow, and YAP/TAZ inhibition suppresses inflammation and retards atherogenesis. Atheroprone-disturbed flow increases whereas atheroprotective unidirectional shear stress inhibits YAP/TAZ activity. Unidirectional shear stress activates integrin and promotes integrin-Gα interaction, leading to RhoA inhibition and YAP phosphorylation and suppression. YAP/TAZ inhibition suppresses JNK signalling and downregulates pro-inflammatory genes expression, thereby reducing monocyte attachment and infiltration. In vivo endothelial-specific YAP overexpression exacerbates, while CRISPR/Cas9-mediated Yap knockdown in endothelium retards, plaque formation in ApoE mice. We also show several existing anti-atherosclerotic agents such as statins inhibit YAP/TAZ transactivation. On the other hand, simvastatin fails to suppress constitutively active YAP/TAZ-induced pro-inflammatory gene expression in endothelial cells, indicating that YAP/TAZ inhibition could contribute to the anti-inflammatory effect of simvastatin. Furthermore, activation of integrin by oral administration of MnCl reduces plaque formation. Taken together, our results indicate that integrin-Gα-RhoA-YAP pathway holds promise as a novel drug target against atherosclerosis.

Abstract-Hypertension and vascular dysfunction result in the increased release of endothelium-derived contracting factors (EDCFs), whose identity is poorly defined. We tested the hypothesis that endothelial cyclooxygenase (COX)-2 can generate EDCFs and identified the possible EDCF candidate. Changes in isometric tension of aortae of young and aged hamsters were recorded on myograph. Real-time changes in intracellular calcium concentrations ([Ca 2ϩ ] i ) in native aortic endothelial cells were measured by imaging. Endothelium-dependent contractions were triggered by acetylcholine (ACh) after inhibition of nitric oxide production and they were abolished by COX-2 but not COX-1 inhibitors or by thromboxane-prostanoid receptor antagonists. 2-Aminoethoxydiphenyl borate (cation channel blocker) eliminated endothelium-dependent contractions and ACh-stimulated rises in endothelial cell [Ca 2ϩ ] i . RT-PCR and Western blotting showed COX-2 expression mainly in the endothelium. Enzyme immunoassay and high-performance liquid chromatography-coupled mass spectrometry showed release of prostaglandin (PG)F 2␣ and prostacyclin (PGI 2 ) increased by ACh; only PGF 2␣ caused contraction at relevant concentrations. COX-2 expression, ACh-stimulated contractions, and vascular sensitivity to PGF 2␣ were augmented in aortae from aged hamsters. Human renal arteries also showed thromboxane-prostanoid receptor-mediated ACh-or PGF 2␣ -induced contractions and COX-2-dependent release of PGF 2␣ . The present study demonstrates that PGF 2␣ , derived from COX-2, which is localized primarily in the endothelium, is the most likely EDCF underlying endothelium-dependent, thromboxane-prostanoid receptor-mediated contractions to ACh in hamster aortae. These contractions involved increases in endothelial cell [Ca 2ϩ ] i . The results support a critical role of COX-2 in endothelium-dependent contractions in this species with an increased importance during aging and, possibly, a similar relevance in humans. Key Words: endothelium-derived contracting factors Ⅲ cyclooxygenase-2 Ⅲ thromboxane-prostanoid receptor Ⅲ aging Ⅲ aorta B esides neuronal and hormonal regulation, vascular tone is modulated locally by a delicate balance between endothelium-derived relaxing (EDRFs) and contracting (EDCFs) factors, 1,2 with the latter being less well-defined but emerging in hypertension, obesity, hyperlipidemia, diabetes, and aging. 3 A number of molecules have been proposed as possible EDCF candidates under pathophysiological conditions. These include prostaglandin (PG)H 2 , thromboxane (TX)A 2 , leukotrienes, endothelin 1, and superoxide anions. The release of these tentative EDCFs can be triggered by acetylcholine (ACh), angiotensins I/II, ADP, and ATP. 4 The contribution of additional cyclooxygenase (COX)-derived metabolites, ie, PGE 2 , PGD 2 , and PGF 2␣ , has been postulated. The precise nature of these EDCFs varies among species and vascular beds. 1,3 Two isoforms of COX have been identified in blood vessels. COX-1 is constitutively expressed and...

Abstract-Sitagliptin, a selective dipeptidyl peptidase 4 inhibitor, inhibits the inactivation and degradation of glucagon like peptide 1 (GLP-1), which is used for the treatment of type 2 diabetes mellitus. However, little is known about the role of GLP-1 in hypertension. This study investigated whether the activation of GLP-1 signaling protects endothelial function in hypertension. Two-week sitagliptin treatment (10 mg/kg per day, oral gavage) improved endotheliumdependent relaxation in renal arteries, restored renal blood flow, and reduced systolic blood pressure in spontaneously hypertensive rats. In vivo sitagliptin treatment elevated GLP-1 and GLP-1 receptor expressions, increased cAMP level, and subsequently activated protein kinase A, liver kinase B1, AMP-activated protein kinase-␣ and endothelial NO synthase in spontaneously hypertensive rat renal arteries. Inhibition of GLP-1 receptor, adenylyl cyclase, protein kinase A, AMP-activated protein kinase-␣, or NO synthase reversed the protective effects of sitagliptin. We also demonstrate that GLP-1 receptor agonist exendin 4 in vitro treatment had similar vasoprotective effects in spontaneously hypertensive rat renal arteries and increased NO production in spontaneously hypertensive rat aortic endothelial cells. 1 Hypertension can cause renal damage if it is not properly controlled.2 The impaired vasodilator response is a risk factor for renal function loss in patients with essential hypertension.3 Persistent hypertension alters functional characteristics of vascular endothelial cells and is associated with impaired vasodilatory function.4 Diminished production and function of endothelium-derived NO leads to endothelial dysfunction, 5 a crucial initial step culminating in vascular events in hypertension.Dipeptidyl peptidase 4 (DPP-4), also known as CD26, is a ubiquitous enzyme detectable in the endothelium.6 Glucagonlike peptide 1 (GLP-1) produced by L-type cells in the intestine, is a substrate for DPP-4. 7 GLP-1 improves glucose use in patients with type 2 diabetes mellitus by increasing insulin secretion and inhibiting glucagon secretion. 8,9 Sitagliptin, a highly selective DPP-4 inhibitor, 10 inhibits the inactivation and degradation of GLP-1, 11 which is used for the treatment of type 2 diabetes mellitus as monotherapy or in combination with other antiglycemic agents, such as metformin. 12The effect of GLP-1 on blood pressure has been reported in both animal and human hypertension.