As climate change raises global temperatures, there remains a notable gap in understanding the body's mechanism of the heat stress defense exhibited by Heat Shock Protein (HSP) within the populations. This study aims to evaluate the expression of heat shock protein 70 (HSP70) in vulnerable populations living in urban and rural areas in response to heat exposure. A comparative cross-sectional study involved 54 urban and 54 rural participants from Klang Valley, Malaysia. This study comprises four methods: Part I involves conducting face-to-face interviews questionnaire; Part II involves monitoring indoor heat exposure and classifying thermal stress using the Universal Thermal Climate Index (UTCI); Part III involves using the reverse-transcription quantitative polymerase chain reaction (RT-qPCR) and Part IV involves using the HSP70 High Sensitivity Enzyme-linked Immunosorbent Assay (ELISA). The findings revealed that urban areas have a higher heat level, classified as strong UTCI thermal stress (32.1oC), whereas rural areas have moderate UTCI thermal stress (31.0oC). In response to heat stress, the urban vulnerable populations exhibited higher HSP70 gene expression (0.167 ± 0.86) compared to the rural (0.154 ± 0.28). A significant difference (p<0.001) in HSP70 protein expression was observed in the plasma of urban compared to rural vulnerable populations. There was a strong association between UTCI heat exposure level and the expression of the HSP70 gene and protein in both vulnerable population groups (p<0.001). Although susceptible to vulnerabilities, the populations demonstrated HSP70 expressions in response to varying levels of heat exposure as a coping mechanism at the cellular level.

The authors have declared no competing interest.

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This study obtained ethical approval from the Ethics Committee for Research Involving Human Subjects of Universiti Putra Malaysia (UPM) (Ref. No.: JKEUPM-2022-222). Permission from the respondents was obtained through written informed consent.

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