Heat stress genes in hypertension

Area of Science:

• Cardiovascular Research
• Genetics
• Molecular Biology

Background:

• Genetically hypertensive animals, like spontaneously hypertensive rats (SHR), exhibit heightened sensitivity to thermal stress compared to normotensive controls.
• Genetic linkage studies indicate that thermosensitivity in SHR segregates with elevated blood pressure, identifying a genetic locus for hypertension.

Purpose of the Study:

• To investigate the molecular mechanisms underlying increased thermosensitivity in genetically hypertensive animals.
• To explore the role of heat shock protein 70 (hsp70) gene expression in hypertension and thermal stress response.

Main Methods:

• Utilized genetically hypertensive animal models (SHR) and normotensive controls.
• Conducted genetic breeding experiments and analyzed gene transcription rates.
• Examined hsp70 gene expression in neonatal cardiomyocytes and vascular smooth muscle cells.

Main Results:

• Hypertensive animals demonstrated greater thermosensitivity and elevated accumulation of hsp70 messenger RNA (mRNA).
• Increased hsp70 transcription was observed in SHR cardiomyocytes and vascular smooth muscle cells, suggesting primary cellular abnormalities.
• Recombinant inbred animal studies implicated RT1 complex genes (major histocompatibility complex) in hypertension development.

Conclusions:

• The heightened thermosensitivity in hypertension is associated with increased hsp70 gene transcription, potentially due to promoter region abnormalities or altered transcription factor activity.
• Findings suggest that hsp70 gene or linked genes within the RT1 complex may play a role in the environmental control of hypertension expression.