Background:
We recently demonstrated that γδ T cells participate in the pathogenesis of hypertension. Evidence also suggests that memory T cells may develop during an initial hypertensive episode, sensitizing mice to develop hypertension to further mild hypertensive challenges. However, whether memory γδ T cells develop and play a role in hypertension remains unknown. Our objective is to determine if memory γδ T cells sensitize mice to develop hypertension in response to a mild hypertensive challenge.
Methods:
Ten-12-week-old C57BL/6J mice were exposed or not to a hypertensive challenge (490 ng/kg/min angiotensin II (Ang II), SC) for two weeks, followed by a two-week washout period, and then infused with a subpressor dose of Ang II (140 ng/kg/min Ang II, SC) for two weeks. Blood pressure was measured via telemetry and central, effector, and resident memory γδ T cells were profiled by flow cytometry.
Results:
Mice exposed to the first hypertensive challenge had a higher systolic blood pressure than the sham group at the end of the subpressor hypertensive challenge (149±6 vs. 122±3 mmHg,
P
<0.001). After 14-days of Ang II infusion, effector memory γδ T cells increased 5.2-fold in the mesenteric artery perivascular adipose tissue (PVAT, 1.25±0.37% vs. 0.24±0.12%,
P
<0.05), and 1.8-fold in the mesenteric lymph nodes (mLN, 1.49±0.03% vs. 0.82±0.15%,
P
<0.05) compared to sham treated mice. After repeated Ang II infusion, central memory γδ T cells decreased by 57% in the aortic PVAT (6.79±1.46% vs. 15.69±2.87%,
P
<0.05), and by 22% in the mLN (0.18±0.01% vs. 0.23±0.01%,
P
<0.05) compared to control mice.
Conclusion:
An initial exposure to a hypertensive stimulus sensitizes mice to develop hypertension to a subsequent subpressor hypertensive challenge and results in the development of memory γδ T cells.
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