Figures & data
Table I. HSF1 activation and HSP induction in various tissue and tissue culture cells at febrile range temperatures.
Figure 1. Hsp72 protein expression is temperature and time dependent. Subconfluent A549 monolayers were exposed to the indicated temperature for the indicated time and then were switched to 37 °C for the remainder of a 24-h incubation. Cells were lysed and analysed for Hsp72 levels by immunoblotting. (A) Band intensities were analysed by direct imaging of the chemiluminescent signal, corrected for loading by normalising to β-tubulin levels, and standardised to 37 °C baseline levels (0). (B) Hsp72 protein levels after 6 h exposure to the indicated temperature between 38.5 °C and 41 °C or to 42 °C for 2 h followed by 4 h recovery at 37 °C were compared. Data are mean ± SE of six experiments. *p < 0.05 versus time 0. †p < 0.05 and ¶p < 0.05 versus 38.5 °C and 39.5 °C, respectively, values at the same exposure time. This research was originally published in Cell Stress and Chaperones [Citation35]. Reprinted with kind permission from Springer Science and Business Media.
![Figure 1. Hsp72 protein expression is temperature and time dependent. Subconfluent A549 monolayers were exposed to the indicated temperature for the indicated time and then were switched to 37 °C for the remainder of a 24-h incubation. Cells were lysed and analysed for Hsp72 levels by immunoblotting. (A) Band intensities were analysed by direct imaging of the chemiluminescent signal, corrected for loading by normalising to β-tubulin levels, and standardised to 37 °C baseline levels (0). (B) Hsp72 protein levels after 6 h exposure to the indicated temperature between 38.5 °C and 41 °C or to 42 °C for 2 h followed by 4 h recovery at 37 °C were compared. Data are mean ± SE of six experiments. *p < 0.05 versus time 0. †p < 0.05 and ¶p < 0.05 versus 38.5 °C and 39.5 °C, respectively, values at the same exposure time. This research was originally published in Cell Stress and Chaperones [Citation35]. Reprinted with kind permission from Springer Science and Business Media.](/cms/asset/25b9d3b8-a75d-41fc-ad87-af877f439a04/ihyt_a_808766_f0001_b.jpg)
Table II. HSF1 activation and HSP expression in infections and injury.
Figure 2. TLR agonists augment Hsp70 expression and release. A and B: RAW cells were incubated with 100 ng/mL LPS, 0.5 µg/mL Pam3CSK4 (Pam3C) or 12.5 µg/mL poly(IC) (pI:C) at 39.5 °C for 6 h (A), or were heat shocked at 42 °C for 2 h, recovered at 37 °C for 4 h (B), lysed, and immunoblotted for Hsp70 and β-tubulin. Lane 1 is the untreated 37 °C control. C and D: RAW cells were incubated with 0, 100, or 1000 ng/mL LPS at 37 or 39.5 °C for 6 h (C) or 24 h (D). Cell culture supernatants were collected and cleared by centrifugation, and Hsp70 was quantified by ELISA and presented as pg/mL. Data presented as the means ± SE (n = 4). * and † denote p < 0.05 versus similarly treated 37 °C cells and 39.5 °C cells with no LPS or hyperthermia-exposed cells, respectively. E and F: Mice implanted with intraperitoneal thermistors were housed at either 25 °C (normothermic, NT) or 36–37 °C (hyperthermic, HT) ambient temperature. For LPS exposure, mice were intratracheally instilled with LPS or sterile phosphate buffered saline (PBS) (control) and housed under normothermic or hyperthermic conditions for 24 h. The lungs were excised, and the homogenates were immunoblotted for Hsp70 and expressed as a ratio to β-actin (E), or lungs were lavaged and Hsp70 quantified by ELISA in the lavage fluid (F). Data are presented as means ± SE (n = 4). *, †, and § denote p < 0.05 versus PBS-treated NT controls, PBS-treated HT mice, and LPS-treated NT mice, respectively. This research was originally published in the Journal of Biological Chemistry [Citation40]. © The American Society for Biochemistry and Molecular Biology.
![Figure 2. TLR agonists augment Hsp70 expression and release. A and B: RAW cells were incubated with 100 ng/mL LPS, 0.5 µg/mL Pam3CSK4 (Pam3C) or 12.5 µg/mL poly(IC) (pI:C) at 39.5 °C for 6 h (A), or were heat shocked at 42 °C for 2 h, recovered at 37 °C for 4 h (B), lysed, and immunoblotted for Hsp70 and β-tubulin. Lane 1 is the untreated 37 °C control. C and D: RAW cells were incubated with 0, 100, or 1000 ng/mL LPS at 37 or 39.5 °C for 6 h (C) or 24 h (D). Cell culture supernatants were collected and cleared by centrifugation, and Hsp70 was quantified by ELISA and presented as pg/mL. Data presented as the means ± SE (n = 4). * and † denote p < 0.05 versus similarly treated 37 °C cells and 39.5 °C cells with no LPS or hyperthermia-exposed cells, respectively. E and F: Mice implanted with intraperitoneal thermistors were housed at either 25 °C (normothermic, NT) or 36–37 °C (hyperthermic, HT) ambient temperature. For LPS exposure, mice were intratracheally instilled with LPS or sterile phosphate buffered saline (PBS) (control) and housed under normothermic or hyperthermic conditions for 24 h. The lungs were excised, and the homogenates were immunoblotted for Hsp70 and expressed as a ratio to β-actin (E), or lungs were lavaged and Hsp70 quantified by ELISA in the lavage fluid (F). Data are presented as means ± SE (n = 4). *, †, and § denote p < 0.05 versus PBS-treated NT controls, PBS-treated HT mice, and LPS-treated NT mice, respectively. This research was originally published in the Journal of Biological Chemistry [Citation40]. © The American Society for Biochemistry and Molecular Biology.](/cms/asset/7071a09f-18ab-4c71-a5ee-68b8f6c7537e/ihyt_a_808766_f0002_b.jpg)
Figure 3. Model of how fever, inflammatory agonists, and Hsp70 interact to cause sepsis. Proposed model of sepsis in which LPS and fever initiate a positive feedback pathway through enhanced Hsp70 expression and release, and subsequent increased TLR activation, Hsp70 expression, and proinflammatory cytokine release. This research was originally published in the Journal of Biological Chemistry [Citation40], © the American Society for Biochemistry and Molecular Biology.
![Figure 3. Model of how fever, inflammatory agonists, and Hsp70 interact to cause sepsis. Proposed model of sepsis in which LPS and fever initiate a positive feedback pathway through enhanced Hsp70 expression and release, and subsequent increased TLR activation, Hsp70 expression, and proinflammatory cytokine release. This research was originally published in the Journal of Biological Chemistry [Citation40], © the American Society for Biochemistry and Molecular Biology.](/cms/asset/213e5fbd-9442-4a3c-894f-c31ec06379ba/ihyt_a_808766_f0003_b.jpg)