Heat Shock Protein 72 Expressing Stress in Sepsis: Unbridgeable Gap between Animal and Human Studies—A Hypothetical “Comparative” Study

Table 1

(a) Results of animal in vivo studies examining the preventive role of intra- or extracellular Hsp72 (Hsp70) expression and Hsp72 (Hsp70) expression in experimental sepsis or sepsis-related pathophysiology. (b) Results of animal in vitro studies examining the preventive role of intracellular Hsp72 (Hsp70) expression in experimental sepsis or sepsis-related pathophysiology. (c) Results of genetic animal studies examining the preventive role of intracellular Hsp72 (Hsp70) expression in experimental sepsis or sepsis-related pathophysiology.

(a)

In vivo	Induction	Organs studied	Expression in cells/Hsp72 challenge	Extracellular Hsp72 levels	Inhibitors	Functional	Pathways	Interleukins	Organ damage	Survival
CLP sepsis rats [18, 19]; LPS-treated rats [20–24] LPS-treated mice [25]	Heat stress	Lungs (4); Heart (1); Splenocytes (1); Rostral Ventrolateral medulla (1); Mitochondrial function (1); Brain (1)	Induced (7)	—	Hsp70 inhibitors (KNK437 or pifithrin-m) abrogated the ability of the thermal treatment to enhance TNF-𝛼 (1)	Alleviated hypotension, bradycardia, sympathetic vasomotor activity (1) EEG and epileptic spikes attenuated (1)	Suppressed iNOS mRNA NF-κB activation, IB kinase activation, IB degradation (1) Prevented downregulation of Grp75, preserved cytochrome c oxidase (1) enhanced phosphorylation of IKK, IkB, NF-κB nuclear translocation, binding to the TNF-𝛼 promoter (1)	Cytokines declined (2) HMGB1 inhibited (1) enhanced LPS-induced TNF-𝛼 production (1)	Reduced (4) Prevented sepsis-associated encephalopathy (1)	Enhanced (6)
LPS-treated mice [26, 27] rats [28–30] sheep [31]; CLP sepsis rats [32, 33]; CPL sepsis mice [34, 35]	Glutamine	Heart (3); Lungs (3); Liver (2); Aorta (1); Kidneys (1); Brain (1); Blood (1); Multiple organs (1)	Induced (7)	Blood samples: increased Hsp72 only after coadministration of Gln and ciprofloxacin [26]	Quercetin blocked Gln-mediated enhancement of Hsp and HSF-1-p expressions and survival benefit (2); LD75 dose of P. aeruginosa and ciprofloxacin in combinations (1)	Prevented ARDS (2); arterial pressure, cardiac contractility restored in the Gln than in the LPS shock (2) Quercetin prevented Gln protection (1) No difference in hemodynamic parameters (1)	Inhibited activation, translocation of NF-κB to the nucleus degradation of IKBalpha, phosphorylation of p38 MAPK, ERK, increased MKP-1 (1) lung HMGB-1 expression NF-κB DNA-binding activity suppressed (1) Reduced peroxide biosynthesis (1)	Attenuated TNF-alpha (3), IL-6. IL-18, MDA, HMGB-1, apoptosis (1) increased IL-10 (1)	Reduced (5)	Enhanced (7)
LPS-treated rats bovine or Ad70 virus or rHsp [36–40]; CLP sepsis rats and tracheas AdHSP [32]	Exogenous rHsp AdTrack or Ad70 virus 72	Liver (1); Peritoneal macrophages (1); MLE-12 cells (1); Myocardium (1); Lungs (1)	Induced (4)	—	—	Normalized hemostasis (2) hemodynamics (2); Biochemical parameters (1)	Inhibited LPS-induced decrease NO expression in macrophages, normalized neutrophil apoptosis (1) inhibited IκB𝛼 degradation and NF-κB, p65 nuclear translocation (2) apoptotic cellular pathways caspases 3, 8, 9 (1)	Modified myeloid cells response to LPS (1) prevented LPS-induced increase in TNF-𝛼 and IL-6 (2) Reduced ICAM-1, attenuated cardiac dysfunction (1)	Attenuated cardiac dysfunction (1) reduced alveolar cell apoptosis (1)	Enhanced (5)

(b)

In vitro	Induction	Organs studied	Intracellular Hsp72 expression	Inhibitors	Pathways	Interleukins	Organ damage	Survival
Murine macrophage-like RAW 264.7 cells [12]	Heat shocked	Macrophages (1)	Cells from HS overexpressed Hsp72 (1)	—	Inhibited phosphorylation of p38, JNK, ERK/MAPK, IκB𝛼 degradation, NF-κB p65 nuclear translocation (1)	HS inhibited HMGB1-induced cytokines TNF-𝛼 and IL-1𝛽 (1)	—	Enhanced (1)
CLP-treated murine peritoneal macrophage cell line RAW264.7 [41] Neonatal rat cardiomyocytes [42]; IEC-18 rat intestinal epithelial cells [43]	Glutamine	Peritoneal macrophages (1); Cardiomyocytes (1); Intestinal epithelial cells (1)	Increased Hsp70 expression (2)	Gln protection mimicked by PUGNA, banished by alloxan (1) DFMO ornithine decarboxylase inhibitor (1)	Reduced LDH, increased O-ClcNAc, HSF-1, transcription activity (1) increased HSF1 binding to HSE (1)	In vitro TNF-𝛼 dose- time-Gln. Dependent In vivo lower intracellular TNF-𝛼 level	Attenuated LPS-induced cardiomyocyte damage (1)	Enhanced (3)
LPS-treated rats [44]; LPS stimulation-mouse macrophage-like cell line (RAW 264.7 cells) [45, 46]	Transfected with Hsp70 plasmid or HS	Myocardium (1); Macrophages (2)	Hsp70 plasmid or HS induced Hsp70 (2)	—	iNOS mRNA completely abolished by HS-Hsp70–transfected cells (1); HS inhibited LPS-induced NF-κB and HSF-1 activity (1) increases both cellular SK1 mRNA and protein levels (1)	—	—	Enhanced (2)
CLP rats, murine lung epithelial-12 cells in culture [47]; Murine macrophage-like RAW 264.7 cells [12]	Exogenous Hsp72	Lungs (1); Macrophages (1)	Overexpression of Hsp72 in RAW/Hsp72 cells (1); —	—	Limited nuclear translocation of NF-κB, phosphorylation of IkappaBalpha (2); Inhibition of the MAP kinases (p38, JNK, and ERK) (1)	Inhibition of the NF-κB - HMGB1-induced release of TNF-𝛼, IL-1𝛽 (1)	Limited NF-κB activation (2)	Enhanced (2)
CLP-treated mice [48]	Arsenite; (Positive control)	Lungs (1)	Induced- Inhibitors blocked Hsp72 expression, (1)	Anti-human Hsp72 (1)	Pretreatment with neutralizing antibodies to Hsp72 diminished neutrophil killing (1)	—	Survivors higher 𝑛 of γ 𝛿T cells (1)	Enhanced (1)

(c)

KO animals	Induction	Organs studied	Intracellular Hsp72 expression	Pathways	Interleukins	Organ damage	Survival
CLP sepsis Hsp70.1/3−/− KO mice [34]	Glutamine	Lungs (1)	Hsp70.1/3−/− mice did not increase Hsp72 (1)	Hsp70.1/3((−/−)) mice increased NF-κB binding/ activation (1)	Increased TNF-𝛼, IL-6 in KO (1)	Increased lung injury in KO (1)	Decreased in KO (1)
CLP sepsis, injection of microorganisms Hsp70−/− KO mice [49]	Imipenem/ cilastatin	Gut (1); Lungs (1)	Hsp70−/−mice did not increase Hsp72 (1)	Increased apoptosis and inflammation	Hsp70−/−increased TNF-𝛼, IL-6, IL-10, IL-1b	KO-increased gut epithelial apoptosis, pulmonary inflammation (1)	Decreased in KO age dependent (1)
LPS-treated mice Hsp−/− or overexpressed Hsp70 [50]	LPS	Intestinal epithelium (1)	Pharmacologic Hsp70 upregulation	Hsp70 reduced TLR4 signaling in enterocytes (1)	Hsp70 reversed TLR4- cytokines, enterocyte apoptosis (1)	Prevented and treated experimental NEC (1)	—
LPS-treated mice overexpressing the human Hspa12b gene [51]	LPS	Heart (1)	Overexpression of HSPA12B	Prevented decrement in the activation of PI3K/protein kinase B signaling in myocardium (1)	Decreased the expression of VCAM-1/ICAM-1 (1)	Decreased leucocyte infiltration in myocardium (1) Attenuated cardiac dysfunction (1)	—

𝑛: number of studies; PBMC: peripheral blood mononuclear cells; LPS: bacterial lipopolysaccharide; CLP: cecal ligation and puncture; TNF-𝛼: tumor necrosis factor-alpha; AdHSP: adenoviral vector Hsp72; Gln: glutamine; HS: heat stress; Hspgene: Hsp70 gene-transfected models; HSF1: HS factor 1; HSE: heat shock element; IKK: IκB kinase; IkB: IkappaBalpha.