Expression of human beta 1,4-galactosyltransferase in gynecological cancer cell lines

We examined the expression of beta 1,4-GT gene products in 11 gynecological cancer cell lines. A 4.7 kb mRNA and protein (54,000 Da and 57,000 Da) were detected by Northern blot and Western blot. Immunocytochemical staining revealed that beta 1,4-GT was localized in the Golgi or ER of tumor cells. An intense beta 1,4-GT mRNA signal was detected in ovarian and cervical cancer cells, whereas the level of beta 1,4-GT mRNA was very low in uterine endometrial cancer cells. We also confirmed that expression of beta 1,4-GT mRNA corresponded to expression of beta 1,4-GT protein. These results suggest that expression of the beta 1,4-GT gene products is higher in human cervical and ovarian cancer cells than in uterine endometrial cancer cells.

Intranephron localization and regulation of the V1a vasopressin receptor during chronic metabolic acidosis and dehydration in rats

The intrarenal localization and role of the V1a vasopressin receptor in body fluid homeostasis are unclear. We investigated the intranephron localization of V1a receptor mRNA and protein using reverse transcription (RT)-competitive polymerase chain reaction (PCR) and immunohistochemistry with a specific polyclonal antibody. To determine whether the V1a receptor is involved in the regulation of acid-base balance, we also examined the effects of acute and chronic metabolic acidosis and dehydration on V1a receptor expression. V1a mRNA was expressed most abundantly in the cortical collecting ducts (CCD) and decreased in the deeper CD. Expression in the glomeruli and thick ascending limbs was low. The immunohistochemical study revealed the presence of the V1a receptor in the glomeruli, the thick ascending limbs and the CD. Dehydration decreased V1a mRNA expression in the CD. Chronic metabolic acidosis increased V1a receptor mRNA expression in the CD but decreased V2 receptor mRNA expression. Western blot analysis revealed up-regulation of the V1a receptor protein in chronic metabolic acidosis. Incubation of microdissected CCD or outer medullary CD (OMCD) in a low-pH (or or low-HCO3-) medium increased the levels of V1a receptor mRNA but decreased V2 receptor mRNA expression. Incubating OMCD with arginine vasopressin (AVP) and the V1a receptor antagonist (OPC21268) increased V2 receptor mRNA expression compared with incubation with AVP alone. These data suggest that V1a receptors are present primarily in the principal and intercalated cells in the CD and that these receptors are involved in the regulation of water and acid-base balance.

Induction of mitochondrial heat shock protein 60 and 10 mRNAs following transient focal cerebral ischemia in the rat

Heat shock proteins (HSPs) 60 and 10 are stress-inducible mitochondrial matrix proteins that form a chaperonin complex that is important for mitochondrial protein folding and function. The effect of cerebral ischemia on mitochondrial HSPs is unclear. The topographical and chronological patterns of HSP60 and HSP10 messenger ribonucleic acid (mRNA) expression and induction were investigated in the rat focal cerebral ischemia model. Focal cerebral ischemia was produced by transient middle cerebral artery occlusion for 30 or 90 min. Expression of mRNAs was analyzed using reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. RT-PCR analysis showed that both HSP60 and HSP10 mRNA levels increased significantly in the ischemic cortex from 4 to 24 h of reperfusion after 30 min of occlusion. In situ hybridization analysis demonstrated significant induction of both mRNAs in the whole ischemic cortex after 30 min of occlusion and in the dorsomedial border (penumbra) of the ischemic cortex and ipsilateral hippocampus after 90 min of occlusion. Expression patterns and the timing of the induction of both HSP60 and HSP10 mRNAs were identical throughout the experiments. Simultaneous induction of the mRNAs for the mitochondrial chaperonins, HSP60 and HSP10, in various regions in focal cerebral ischemia demonstrates that mitochondrial stress conditions persist concomitantly with cytosolic stress conditions in focal cerebral ischemia.

Simultaneous induction of mitochondrial heat shock protein mRNAs in rat forebrain ischemia

Several investigations have postulated evidence of the involvement of apoptosis in delayed neuronal death following brief periods of global cerebral ischemia. Apoptosis may be closely linked to mitochondrial dysfunction. Heat shock protein (HSP) 60 and HSP10 are mitochondrial matrix proteins induced by stress and form the chaperonin complex that is implicated in protein folding and assembly within the mitochondria. This study investigated the induction of these mitochondrial stress protein genes in the hippocampal CA1 region and less vulnerable regions following transient forebrain ischemia. In situ hybridization analysis revealed that the induction pattern of HSP60 mRNA was identical to that of HSP10 mRNA throughout the entire ischemic course. No changes occurred in the expression of both mRNAs after 2 min ischemia. Strong induction of both mRNAs occurred in the CA1 region after 10 min ischemia and persisted until 1 d after reperfusion. In contrast, induction of both mRNAs in the less vulnerable regions was terminated by 1 d after reperfusion. These results demonstrate that mitochondrial stress conditions persist concomitantly with cytosolic stress conditions in regions vulnerable to transient forebrain ischemia.

Specific preinduction of 60-kDa heat shock protein (chaperonin homolog) by TRH does not protect colonic mucosa against acetic acid-induced lesion in rats

In order to study the cytoprotective function of colonic heat shock proteins (HSPs) in vivo, the effect of specific preinduction of HSP60 by thyrotropin-releasing hormone (TRH) administration on the development of acetic acid-induced colonic mucosal lesion was investigated. Expression of 60-kDa, 72-kDa, and 90-kDa heat shock proteins (HSP60, HSP72, and HSP90, respectively) in rat colonic mucosa was investigated by western blot and immunohistochemical analyses before and after TRH administration. Following pretreatment with or without TRH administration, the rats received intrarectal infusion of 5% acetic acid. The colonic mucosal damage was macroscopically evaluated 24 hr after the intrarectal infusion of acetic acid. Expression of HSP60 was significantly increased by TRH administration in the colonic mucosa, whereas HSP72 and HSP90 did not increase. Immunohistochemical study also showed a significant increase in HSP60 in colonic mucosal cells, especially at the surface of the colonic mucosa after TRH administration. No histopathologic alteration was observed in the colonic mucosa after TRH administration. The colonic mucosal damage caused by intrarectal infusion of 5% acetic acid was not prevented by preinduction of HSP60. We demonstrated that specific preinduction of HSP60 by TRH administration did not show cytoprotective function in the colonic mucosa, although this protein plays a crucial role for cytoprotection in the pancreatic acinar cells. Our results indicate that the role of HSP60 may be different in each organ with respect to cytoprotection.

A peptide derived from pICln induced a strong hypotonic resistance in Escherichia coli cells

We demonstrated previously that expression of rat pICln in Escherichia coli conferred a strong resistance to hypotonic stress. To define the intramolecular functional domain responsible for the resistance, molecular dissection of pICln was performed and the obtained peptides were expressed in E. coli. The cells expressing the peptides were exposed to a hypotonic solution, and their 'survival rates' were observed. The cells expressing only the peptides including the second acidic domain of pICln exhibited significantly higher 'survival rates' after hypotonic stress. The functional domain against hypotonicity was finally narrowed down to a peptide consisting of a 46-amino acid residue, P107-152. We conclude that the expression of P107-152 in E. coli cells could enhance their resistance to a hypotonic environment.

Mammalian HSP60 is a major target for an immunosuppressant mizoribine

It has been reported that immunosuppressant cyclosporin A or FK506 binds to immunophilins in the cell and that these immunophilins make a complex with molecular chaperones HSP70 or HSP90. Although mizoribine has been used clinically as an immunosuppressant, immunophilins of the agent have not yet been fully understood. We investigated their specific binding proteins using mizoribine affinity column chromatography and porcine kidney cytosols. By increasing mizoribine in the eluant from the column, two major proteins (with molecular masses of 60 and 43 kDa) were detected by SDS-polyacrylamide gel electrophoresis. Based on the amino acid sequence analysis of these proteins, 60- and 43-kDa mizoribine-binding proteins were identified with HSP60 and cytosolic actin, respectively. A considerable amount of actin was also eluted from the affinity column by nucleotides, but a very low quantity of HSP60 was eluted under the same conditions. On the other hand, HSP60 was eluted as a major protein in the eluant that was eluted preferentially, with nucleotide followed by mizoribine. Actin was also detected in the eluant, but the quantity of the protein was very low. These results indicated that HSP60 has high affinity to mizoribine, and the interaction was also observed on surface plasmon resonance analysis. Although HSP60 or GroE facilitated refolding of citrate synthase in vitro, mizoribine interfered with the chaperone activity of HSP60. On different types of mizoribine affinity columns, HSP60 or actin recognized the NH(2) group of mizoribine, and this group may be a functional group of the agent.

A novel chaperone-activity-reducing mechanism of the 90-kDa molecular chaperone HSP90

The 90-kDa heat shock protein (HSP90) acts as a specific molecular chaperone in the folding and regulates a wide range of associated proteins such as steroid hormone receptors. It is known that HSP90 possesses two different chaperone sites, both in the N- and C-domains, and that the chaperone activity of HSP90 is blocked by binding of geldanamycin (GA) to the N-domain, the same as the ATP-binding site. Here we show that Cisplatin [cis-diamminedichloroplatinum (II), CDDP], an antineoplastic agent, associates with HSP90 and reduces its chaperone activity. In order to analyse the binding proteins, bovine brain cytosols were applied to a CDDP-affinity column and binding proteins were eluted by CDDP. In the elutants, only 90-kDa protein bands were detected on SDS/PAGE, and the protein was cross-reacted with the anti-HSP90 antibody on immunoblotting. No protein bands were detected in the elutants from the control column on SDS/PAGE. These results indicated that CDDP has a high affinity for HSP90. On CD spectrum analysis, the binding of CDDP to HSP90 resulted in a conformational change in the protein. Although HSP90 inhibited the aggregation of citrate synthase as a molecular chaperone in vitro, the activity was suppressed almost completely in the presence of CDDP. Mg/ATP has an influence on the chaperone activity to some extent. The CDDP binding region of HSP90 is near the C-terminal which is quite different from the GA-binding site. Our results suggest that the chaperone activity of HSP90 may be inhibited by the binding of CDDP or GA by different mechanisms.

pI(Cln) and cytosolic F-actin constitute a heteromeric complex with a constant molecular mass in rat skeletal muscles

To elucidate the function of pI(Cln), its localization in subcellular organellae was investigated. A specific polyclonal anti-pI(Cln) antibody detected the soluble 38-kDa pI(Cln) exclusively in the cytosols of rat heart, lung, liver, spleen, skeletal muscle, testis, and brain, but not rat kidney. pI(Cln)-associated proteins in skeletal muscle were also analyzed. Native-gradient PAGE showed a single 340-kDa protein band reactive to anti-pI(Cln) antibody. This band also stained with anti-actin antibody. Two-dimensional PAGE and immunoprecipitation analysis indicated that all of the pI(Cln) was present in association with actin of a constant length: the molecular ratio of pI(Cln) to actin was roughly 1:7. In addition, all actin in the cytosol fractions was found in association with pI(Cln). These results suggest the possibility that skeletal muscle pI(Cln) controls the length of cytosolic F-actin.

Association of 72-kDa heat shock protein expression with adaptation to aspirin in rat gastric mucosa

It is well documented that gastric mucosa can increase its resistance to mucosal damage caused by aspirin during repeated long-term administration of aspirin. However, the underlying mechanism of this adaptation is not well established. In the present study, we investigated the effect of long-term (chronic) administration of aspirin on expression of heat shock proteins (HSPs), which are known as endogenous cytoprotectants, in rat gastric mucosa. Rats were administered aspirin (100 mg/kg) daily for up to 20 days. After various periods of aspirin administration, a high dose of aspirin (250 mg/kg) was administered, and the mucosal damage was assessed. Expression of heat shock proteins (HSPs) in gastric mucosa was evaluated by Western blot. Intracellular localization of each HSP was studied immunohistochemically. Prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels were also investigated. Long-term aspirin administration resulted in development of resistance to aspirin-induced mucosal damage, and the increase of HSP72 expression correlated with mucosal resistance to aspirin. No significant increase was observed in HSP60 and HSP90 levels. Immunohistochemical study showed an increase of HSP72 in the cytoplasm of mucosal surface cells. The PGE2 level was suppressed and no change in the level of LTB4 was observed. It is possible that HSP72 could play important roles in gastric mucosal adaptation when the PGE2 level is suppressed by NSAIDs.

Overexpression of the human 72 kDa heat shock protein in renal tubular cells confers resistance against oxidative injury and cisplatin toxicity

BACKGROUND

Recent studies have shown that the 72-kDa heat shock protein (HSP72) can be induced in renal tubular cells by a variety of stress conditions, and suggested its cytoprotective function. We have tested this hypothesis directly by transfection studies.

METHODS

LLC-PK1 cells (porcine renal tubular epithelial cells) were stably transfected with pBK-CMV or pBK-CMV containing the human HSP72 gene (pBK-CMV-HSP72). These cells were then treated with various concentrations of hydrogen peroxide or cisplatin. The cell viability and lytic cell damage were determined by the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay and lactate dehydrogenase release assay.

RESULTS

Immunoblot and immunocytochemical analyses showed the high level expression of HSP72 in LLC-PK1 cells transfected with pBK-CMV-HSP72. In addition, the expression of other major HSPs (HSP90, HSP73, HSP60 and HSP27) was not affected by transfection. LLC-PK1 cells overexpressing HSP72 were significantly more resistant to hydrogen peroxide and cisplatin treatments than control cells.

CONCLUSION

These results indicate that overexpressed HSP72 plays a direct role in protecting renal tubular cells against oxidative injury and cisplatin toxicity.

Intranephron distribution and regulation of endothelin-converting enzyme-1 in cyclosporin A-induced acute renal failure in rats

Endothelin-1 (ET-1) is thought to play a significant role in acute renal failure induced by cyclosporin A (CsA). The cDNA sequence encoding endothelin-converting enzyme-1 (ECE-1), which produces the active form of ET-1 from big ET-1, was recently reported. To elicit the role of ECE-1 in the glomerular and tubular dysfunction induced by CsA, the effects of CsA on mRNA and protein expression of ECE-1 in rat kidney and on mRNA expression of prepro-ET-1 and ET A- and B-type receptors in glomeruli were studied. ECE-1 mRNA was detected in glomeruli and in whole nephron segments. ECE-1 mRNA expression was downregulated in all nephron segments at 24 h after CsA injection. Protein levels were also downregulated in glomeruli and in the outer and inner medulla. CsA rapidly increased prepro-ET-1 mRNA expression in glomeruli at 30 to 60 min after injection; this rapid increase was followed by an increase in plasma ET-1 levels. These increases were followed by decreased expression of ECE-1, ET A-type receptor, and ET B-type receptor mRNA at 6 h after injection, and serum creatinine levels were increased at 24 h after CsA injection. It is suggested that downregulation of glomerular and tubular ECE-1 expression may be caused by increased ET-1 synthesis in CsA-induced acute renal failure.

Effect of preinduction of heat-shock proteins on acetic acid-induced small intestinal lesions in rats

Bowel dysfunction such as irritable bowel syndrome caused by stress is well described. Previous reports suggest that stress is known to cause the release of endogenous substances such as catecholamine, beta-endorphine, 5-hydroxytryptamine, corticotropin-releasing factor, and thyrotropin-releasing hormone (TRH). However, the role played by these neurohormonal mediators in bowel dysfunction under stress conditions is not well known. We investigated the influence of water-immersion stress or TRH administration on the expression of 60-kDa, 72-kDa, and 90-kDa heat-shock proteins (HSP60, HSP72, and HSP90, respectively) in rat small intestinal mucosa by Western blot and immunohistochemical analyses. The cytoprotective function of preinduced HSPs on experimentally induced mucosal damage also was studied. In order to investigate the influence of preinduction of HSP60 on small intestinal damage, the small intestinal lumen was perfused with 1.5% acetic acid 1 ml/min for 15 min with or without pretreatment with water-immersion stress or TRH administration. Expression of HSP60 was significantly increased by water-immersion stress or TRH administration in the small intestinal mucosa, whereas HSP72 and HSP90 did not increase. Interestingly, expression of this protein showed the biphasic peak pattern after water-immersion stress or TRH administration. Each peak was observed 3-6 hr and 21-24 hr after the initiation of water-immersion stress or TRH administration. Immunohistochemical study also showed a significant increment of HSP60 in both the cytoplasm and nuclei of the small intestinal mucosal cells. No histopathologic alteration was observed in rat small intestinal mucosa after each treatment. Small intestinal damage caused by 1.5% acetic acid perfusion was not influenced by preinduction of HSP60. We demonstrated that water-immersion stress or TRH administration specifically induced HSP60, although preinduction of this protein did not show a cytoprotective function in the small intestinal mucosa.

Expression of pI(Cln) in Escherichia coli gives a strong tolerance to hypotonic stress

We amplified the coding region DNA sequence from a rat renal pI(Cln) cDNA by PCR and expressed the protein in Escherichia coli cells. The cells were exposed to hypotonic conditions followed by spreading them onto LB plates for subsequent colony survival assay. The present study demonstrated that the cells expressing pI(Cln) exhibit a strong resistance to hypotonic stress. Moreover, the resistance was specifically inhibited by extracellular ATP and some anion channel inhibitors. These findings indicate that the expression of pI(Cln) directly confers tolerance to hypotonic stress, and pI(Cln) is concluded to be an important molecule for cell-volume regulation.

pICln predominantly localizes at luminal surface membranes of distal tubules and Henle's ascending limbs

We produced a highly specific antibody to the C-terminal peptide sequence of pICln. It recognized pICln with a 38-kDa molecular mass on SDS-polyacrylamide gel electrophoresis, coinciding with that previously reported. During native polyacrylamide gel electrophoresis, three immunoreactive bands (38, 70, and 130 kDa) were detected. The isoelectric point of pICln was calculated to be 4.0. Subcellular localization study showed the presence of pICln in the soluble and microsomal fraction. pICln can be easily solubilized from the membrane fraction with Triton X-100. From immunohistochemical observations, we found pICln to be obviously located on the luminal surface membranes of the distal tubules and Henle's loop ascending limbs, and it can also be found inside proximal tubular cells. The present results suggested that pICln functions as a "cytosolic anchor = membrane insertion" model, and it plays important roles in the "urine dilution segment" cells of nephrons.

Induction of fructose 1,6-bisphosphatase in HL-60 leukemia cells by retinoic acid

The expression of the fructose 1,6-bisphosphatase gene in HL-60 cells was induced by retinoic acid. The levels of mRNA, enzyme activity and enzyme protein in the cell line began to rapidly increase after culturing with retinoic acid for 72 h. Retinoic acid dose-dependently increased the enzyme activity with maximal stimulation at 1 microM. The responses of the fructose 1,6-bisphosphatase gene expression by retinoic acid were markedly slower than those of the enzyme expression by 1alpha,25-dihydroxyvitamin D3. When HL-60 cells were cultured in the presence of both retinoic acid and 1alpha,25-dihydroxyvitamin D3, the effects of the two agents on enzyme activity, protein and mRNA were additive.

Novel 30 kDa protein possessing ATP-binding and chaperone activities

A 30 kDa protein was purified from pig liver cytosol by using ATP-Sepharose and Green A column chromatography. The partial amino acid sequences of the protein (95 amino acid residues) had no similarity with any proteins recorded in data banks. The protein was able to form a stable complex with unfolded dihydrofolate reductase (DHFR). The spontaneous refolding of chemically denatured DHFR was arrested by the 30 kDa protein. This inhibition presumably results from the formation of a stable complex between the 30 kDa protein and DHFR. Bound DHFR could be released from the protein with ATP. The protein also showed protease resistance in an ATP-dependent manner. Incubation of the 30 kDa protein with 5 mM ATP resulted in its resistance to V8 protease or to trypsin treated with 1-chloro-4-phenyl-3-L-toluene-p-sulphonamidobutan-2-one. Divalent cations enhanced the ATP-protection effect. CD analysis of the 30 kDa protein showed that ATP induced an increase in the beta-pleated sheet content and a decrease in the alpha-helix content of the 30 kDa protein. These results suggest that the 30 kDa protein, a novel cytosolic protein, might have an affinity for ATP, a chaperonin activity, and and an ATP-protection effect against some proteases in vivo.

Induction of a 72-kDa heat shock protein and cytoprotection against thioacetamide-induced liver injury in rats

Heat shock proteins are ubiquitous intracellular proteins induced by various physiological stress-related events. A 72-kDa heat shock protein (HSP72) has been reported to be an endogenous cytoprotectant in variety of cells in vitro. In order to study the cytoprotective function of HSP72 in the liver, the effect of preinduction of HSP72 in rat liver by systemic hyperthermia on thioacetamide-induced hepatic injury was investigated in this study. Expression of HSP72 in the liver was investigated by immunoblot and densitometric analysis. Rats were injected with thioacetamide (100 mg/kg, subcutaneously) with or without preinduction of HSP72 by hyperthermia. Serum AST and ALT concentrations were measured before and after thioacetamide injection in both group. Histologic alteration of the liver was evaluated also. Systemic hyperthermia (42.5 degrees C, 20 min) significantly induced HSP72 in the liver. Thioacetamide-induced hepatic injury was clearly prevented by preinduction of HSP72 by hyperthermia. Prevention of hepatocyte damage was more clear in the area around central veins where HSP72 induction was apparent. Our findings might suggest that HSP72 has an important function in the liver with respect to cytoprotection. These results might be important for understanding the mechanism of "adaptive cytoprotection" in the liver mediated by the function of heat shock proteins as "molecular chaperons" as reported in vitro.

Differential induction of HSP60 and HSP72 by different stress situations in rats. Correlation with cerulein-induced pancreatitis

We previously reported that water-immersion stress specifically induced the synthesis of a 60-kDa heat-shock protein (HSP60, chaperonin homolog) in pancreatic cells and preinduction of HSP60 completely prevented development of cerulein-induced pancreatitis in the rat in an HSP60 quantitatively dependent manner. In order to study the cytoprotective function of a 72-kDa heat-shock protein (HSP72, stress-inducible hsp70), the effect of specific preinduction of HSP72 by hyperthermia on cerulein-induced pancreatitis was investigated and compared with the effect of preinduction of HSP60 in this study. Expression of HSP60 and HSP72 in the pancreas was investigated by immunoblot before and after water immersion or hyperthermia. Following pretreatment with water-immersion stress or hyperthermia, the rats were injected with cerulein (40 micrograms/kg, intraperitoneally). The pancreas wet weight and serum amylase concentration were measured before and after cerulein injection. Hyperthermia (42.5 degrees C, 20 min) specifically induced HSP72 in the pancreas. The synthesis of HSP60 was specifically induced by water-immersion stress in the pancreas. Cerulein-induced pancreatitis was clearly prevented by specific preinduction of HSP60 by water-immersion stress. However, preinduction of HSP72 by hyperthermia had no preventive effect on cerulein-induced pancreatitis. Our findings suggest that HSP60 and HSP72 have distinct functions in the pancreas, and their induction mechanisms are also different in vivo. These results could be important for understanding the mechanism of "adaptive cytoprotection" in the pancreas mediated by heat-shock proteins.

Purification and localization of a 25-kD porcine renal puromycin aminonucleoside-binding protein

BACKGROUND

Reactive oxygen species (ROS) are considered to have a role in the progression of puromycin aminonucleoside (PAN) nephrosis. However, the exact mechanism by which PAN induces ROS in this model is little known. In the present study, we attempted to purify a candidate for the target protein from PAN nephrotoxicity.

METHODS

Using PAN-affinity column chromatography, a series of PAN-binding proteins was isolated from porcine renal extracts. We produced a specific antibody against a 25-kD protein eluted from the PAN-affinity matrix, and then developed a method to purify this protein. A partial amino acid sequence of the 25-kD PAN-binding protein was determined, and its tissue distribution was examined by immunoblot and immunohistochemical studies.

RESULTS

The purified 25-kD PAN-binding protein was identified as a renal homolog of a new member of NAD(P)H:quinone oxidoreductases (NQOs, EC 1.6.99.2) that suppress the semiquinone and superoxide anion formation in cells, designated NQO2. Immunoblot analysis revealed a higher expression of the 25-kD PAN-binding protein in the kidney, brain, and liver among porcine major organs. Immunohistochemical studies showed an intrarenal distribution of this protein in epithelial cells of the glomeruli and tubules, mesangial cells, and vascular smooth muscle cells.

CONCLUSIONS

We have purified the renal homolog of NQO2 as a PAN-binding protein, and shown its unique tissue expression. PAN may bind to the NQO2 homolog and inhibit its function in the renal target cells. This is presumed to result in an increase of ROS in the kidney with PAN nephrosis.

Effect of preinduction of heat shock proteins on acetic acid-induced colitis in rats

In order to study the cytoprotective function of heat shock proteins (HSPs) in vivo, the effect of preinduction of HSPs by hyperthermia on acetic acid-induced colitis was investigated. Expression of 60-kDa, 72-kDa, and 90-kDa heat shock proteins (HSP60, HSP72, and HSP90, respectively) in rat colonic mucosa was investigated by Western blot analysis and immunohistochemical study before and after hyperthermia. Following pretreatment with or without hyperthermia, the rats received intrarectal infusion of various doses of acetic acid. The colonic mucosal damage was evaluated by macroscopic and microscopic assessments 24 hr after the intrarectal infusion of acetic acid. Expression of HSPs was significantly increased by hyperthermia in rat colonic mucosa. Immunohistochemical study also showed the increments of HSPs in the colonic mucosal cells after hyperthermia. Acetic acid-induced colitis was dramatically prevented by pretreatment with hyperthermia when HSP72 and HSP90 were preinduced. On the other hand, induction of HSP60 did not correlate with mucosal protection. Our findings suggest that HSP72 and HSP90 may have cytoprotective function against acetic acid-induced mucosal damage. These results may be important for understanding the mechanism of "adaptive cytoprotection" mediated by HSPs.

Effect of pre-induction of heat shock proteins on indomethacin-induced small-intestinal lesion in rats

Systemic hyperthermia induces the synthesis of heat shock proteins (HSPs) in several organs. However, the mechanism of induction and the functions of HSPs in the small-intestinal mucosa have not been established. We examined the expression of HSPs in the small-intestinal mucosa after systemic hyperthermia, and evaluated the cytoprotective function of pre-induced HSPs on experimentally induced mucosal damage. HSP expression was investigated by Western blot and densitometric analysis before and after hyperthermia (42.5 degrees C; 20 min). Expression of a 72-kDa heat shock protein (HSP72) and a 73-kDa heat shock protein (HSP73), both of which are endogenous cytoprotectants in vitro significantly increased, peaking 6-9 h after hyperthermia, without any pathologic alterations, whereas the expression of a 60-kDa heat shock protein (HSP60) did not increase. To investigate the influence of pre-induction of HSPs on small-intestinal damage, rats received indomethacin (10 mg/kg; orally) with or without pre-treatment with hyperthermia. Small-intestinal damage caused by indomethacin was not influenced by pre-induction of HSP72 and HSP73. We demonstrated that systemic hyperthermia induced HSP72 and HSP73, although pre-induction of these proteins did not have a cytoprotective function in the small-intestinal damage caused by indomethacin.

Novel colorectal adenocarcinoma-associated 40- and 47-kDa protein antigens recognized by anti-60-kDa heat shock protein antibody

Expression of 40- and 47-kDa proteins recognized by anti-60-kDa heat shock protein antibody was investigated in colorectal adenocarcinoma tissue. In all cases of colorectal adenocarcinoma tissue (n = 9), 40- and 47-kDa proteins were detected by immunoblot analysis. However, expression of these two proteins was extremely low or was not expressed in control tissue. There was no correlation between the quantity of these two bands and histologic type or the location of the tumors. Our results first demonstrate the accumulation of structurally altered 60-kDa heat shock protein-associated antigens in carcinoma tissue and suggest that these two proteins could be a possible candidate for tumor-specific 60-kDa heat shock protein-related protein antigens.

Induction and intracellular localization of a 72-kDa heat shock protein in rat gastric mucosa after water-immersion stress

We investigated the expression and changes in the intracellular localization of a 72-kDa heat shock protein (HSP72) in rat gastric pyloric and fundic mucosa before and after water-immersion stress. Severe mucosal damage was found in the fundic mucosal area of the stomach after this stress. However, no mucosal lesion developed in the pyloric mucosal area. HSP72 in both the soluble and insoluble fractions of the pyloric and the fundic mucosal areas was significantly increased after water-immersion stress, peaking 6h after the initiation of the stress. The increase in HSP72 was more significant in the pyloric mucosal area than in the fundic mucosal area under both normal and stress conditions. The increase of HSP72 in the pyloric mucosal cells occurred prior to the formation of the mucosal lesions, whereas the increase of HSP72 in the fundic mucosal cells was observed after ulcer formation. An immunohistochemical study showed that HSP72 was constitutively expressed in the cytoplasm of the gastric mucosal cells, and that the intranuclear induction of HSP72 was remarkably intense in the pyloric mucosal cells, especially in the proliferative zone, compared with the fundic mucosal cells. Our results may suggest that HSP72 has an important cytoprotective function in gastric mucosal cells and that there is a "biophysical" difference between pyloric and the fundic mucosal cells.

Induction of 73-kDa and 90-kDa heat shock protein expression in HL60 cells during differentiation

We investigated the expression of heat shock proteins HSP73 and HSP90 in human promyelocytic line HL60 during their differentiation induced by phorbor ester and all trans retinoic acid (ATRA). Polyclonal antibodies which had been raised against HSPs purified from bovine brains were used to detect human HSPs. Semiquantitation of HSPs was performed by immunoblotting. Induction of monocytoid and granulocytoid differentiation with phorbor ester and ATRA was accompanied by increased expression of HSP73 and HSP90 with distinct kinetics. Increased expression of both HSPs was confirmed by immunocytochemical studies. Our results suggest that HSP73 and HSP90 may be involved in differentiation of HL60 cells.

Induction of heat-shock proteins HSP73 and HSP90 in rat kidneys after ischemia

We examined rat kidneys for serial expressions of two major heat-shock proteins (HSPs), HSP73 and HSP90, after 60 min of unilateral renal ischemia up to day 28. Immunohistochemical studies showed that HSP73 and HSP90 were rapidly induced in the cytoplasm of injured epithelial cells of the S3 segment of proximal tubules and were again induced in the cytoplasm of regenerative cells in this segment from day 3. In epithelial cells of the Henle's loops, HSP90 was also induced in the cytoplasm of both injured and regenerative cells, but HSP73 was not induced in this portion. Furthermore, a transient accumulation of HSP73 into the nucleus was observed in epithelial cells of papillary collecting ducts shortly after ischemia. Serial immunoblot analysis of isotonic buffer extractable fractions from ischemic kidneys revealed the induction of both HSP73 and HSP90 in the degenerative and regenerative phases: the maximal inductions in the two phases were at 3-6 and on days 5-7, respectively. These results demonstrate that HSP73 and HSP90 are induced in injured tubular epithelial cells with a regional heterogeneity during the degenerative and regenerative phases after renal ischemia and suggest that these HSPs are involved in the process of postischemic cellular recovery.

Induction and intracellular localization of 90-kilodalton heat-shock protein in rat kidneys with acute gentamicin nephropathy

BACKGROUND

We previously reported the induction of 73-kilodalton heat-shock protein (HSP73) in injured tubular epithelial cells in rat kidneys with gentamicin-induced acute renal failure. In the present study, we examined serial expression of 90-kilodalton heat-shock protein (HSP90), another major HSP, in this animal model.

EXPERIMENTAL DESIGN

Sprague-Dawley rats received gentamicin (80 mg/kg/day) for 14 days and developed acute proximal tubular injury. Serial immunohistochemical localization of HSP90 was observed at both light microscopic and electron microscopic levels, using a specific antibody against HSP90. In addition, serial renal extracts were analyzed by immunoblot.

RESULTS

On light microscopy, HSP90 was induced in injured proximal tubular epithelial cells and accumulated in fine granules 36 hours after the gentamicin exposure. The size and number of these granules gradually increased to Day 12 and decreased from Day 18, and the granules disappeared on Day 27. Electron microscopy showed the accumulation of HSP90 in the swollen lysosomes and the nucleoli of the injured proximal tubular epithelial cells. On serial immunoblot analysis of renal extracts, increased amounts of HSP90 were found in association with the induction of HSP90 in injured cells. Furthermore, on immunoblot of nuclear fractions from kidneys at Days 0 and 6, HSP90 was detected in the fraction at Day 6.

CONCLUSIONS

These results demonstrate that HSP90 is induced in the lysosomes and the nucleoli of damaged cells during the course of gentamicin-induced acute tubular injury. HSP90 may have roles in the disposition of degenerated proteins and in the new protein synthesis for the protection and repair of target cells from gentamicin nephrotoxicity.

Benign prostatic hypertrophy affects the endothelin receptor density in the human urinary bladder and prostate

The effects of benign prostatic hypertrophy (BPH) on the endothelin (ET) receptor density in the lower urinary tract tissues were studied using radioligand binding techniques. Saturation experiments revealed that there were significant amounts of the binding sites for the ET isoforms (ET-1, -2, -3) in the human bladder and prostate in both prostate hypertrophy (PH) and nonhypertrophy (NPH) patients. Autoradiograms of hypertrophic adenoma showed that ET-1 receptors were localized in both the stromal and glandular tissue. In the bladder and the prostate, the KD values were not significantly different between the PH and NPH groups. In the bladder dome, the Bmax values of 125I-ET-1, -2 and -3 decreased significantly in the PH groups, while, in the adenoma, they increased significantly in the PH group. BPH was found to affect the ET receptor density in both the bladder and the prostate. These data suggest that ETs are involved in the pathophysiology of BPH.

Muscarinic cholinergic receptor subtypes in human detrusor muscle studied by labeled and nonlabeled pirenzepine, AFDX-116 and 4DAMP

The densities of M1, M2 and M3 muscarinic receptors in human detrusor muscle were measured using 3H-pirenzepine (3H-PZP), 3H-AFDX-116 (3H-AFDX) and 3H-4-diphenyl-acetoxy-N-methyl-piperidine methidide (3H-4DAMP). The affinities of PZP, AFDX and 4DAMP for human detrusor were determined in inhibition experiments with 3H-quinuclidinyl benzilate (3H-QNB). Saturation experiments with 3H-PZP, 3H-AFDX and 3H-4DAMP revealed the presence of M1, M2 and M3 receptors in human detrusor. The KD values (nM) and the Bmax values (fmol/mg protein) (mean +/- SD, n = 6) were 0.84 +/- 0.15 and 13.04 +/- 1.54 for 3H-PZP, 0.68 +/- 0.21 and 9.30 +/- 1.10 for 3H-AFDX, and 0.25 +/- 0.13 and 102.1 +/- 7.40 for 3H-4DAMP. These data indicate that the bladder muscarinic receptors consist mainly of the M3 subtype. Nonlabeled PZP, AFDX and 4DAMP inhibited the 3H-QNB binding to human detrusor with Ki values (nM) (mean +/- SD, n = 6) of 243 +/- 62.5, 59.7 +/- 15.3, 2.69 +/- 0.96, respectively. Human detrusor was found to have a high affinity for 4DAMP. These data suggest that M3 muscarinic receptors are biochemically predominant in human detrusor muscle.

Regulation of 60-kDa heat shock protein expression by systemic stress and 5-hydroxytryptamine in rat colonic mucosa

Bowel dysfunction such as irritable bowel syndrome caused by stress is well described. Previous reports suggest that 5-hydroxytryptamine (5-HT) mediates alteration of bowel motility. In this study, the effects of water-immersion stress and the administration of 5-HT on the expression of a 60-kDa heat shock protein (HSP60) in rat colonic mucosa were investigated. The effect of YM-060, a 5-hydroxytryptamine 3 (5-HT3) receptor antagonist, on the expression of this protein was also studied. Water-immersion stress and the administration of 5-HT induced synthesis of HSP60 in rat colonic mucosa. The induction of HSP60 and the number of defecations were clearly inhibited by the oral administration of YM-060. Our results suggest that the induction of HSP60 in rat colonic mucosa by water-immersion stress may be associated with gastrointestinal motility mediated by 5-HT, especially via 5-HT3 receptors.

Induction and turnover of fructose 1,6-bisphosphatase in HL-60 leukemia cells by calcitriol

Fructose 1,6-bisphosphatase mRNA and enzyme activity in HL-60 cells were rapidly and markedly induced by calcitriol (formerly known as 1 alpha,25-dihydroxyvitamin D3). The activity reached 70-80 times the basal level after 96 h. The enzyme activity in the cells incubated for 96 h with calcitriol decreased immediately after its withdrawal but after a 24-h incubation the activity in the cells continued to increase slightly and then decreased slowly. Calcitriol increased the enzyme activity dose-dependently with maximal stimulation at 10 nM and half-maximal at 2.1 nM. The rate of synthesis of fructose 1,6-bisphosphatase almost paralleled the increase in mRNA level during treatment with calcitriol. When calcitriol was removed from media after incubation for either 24 h or 96 h, fructose-1,6-bisphosphatase mRNA and fructose-1,6-bisphosphatase synthesis decreased rapidly to the basal level. The enzyme was only slightly degraded in the cells incubated with calcitriol for 24 h followed by the subsequent culture without calcitriol but it was degraded with a half-life estimated to be approximately 64 h in the same cells followed by culturing with calcitriol. In the cells incubated for 96 h, the same degradation rate (i.e. half-life approximately 64 h) was observed irrespective of the following culture with or without calcitriol. Calcitriol did not affect the degradation rate of total soluble proteins.

Heat shock protein 70 in rat liver with necrosis and regeneration induced by thioacetamide

Heat shock protein (hsp), which changes both its concentration and localization in reaction to stresses such as heating, ischemia, etc., is thought to protect protein structure and act as a chaperone in intracellular transportation. We examined one of the hsps, hsp 70, in rat liver with necrosis and regeneration produced by thioacetamide (TAA). Hsp 70 was determined by immunoblotting and detected histologically by immunostaining, using a specific antibody. Generally, hsp 70 moves from the cytosol to the nucleus, where it concentrates 15 min after TAA injection. After 15 min, hsp 70 was not detected in the nuclei of hepatocytes around the central vein, where the hepatocytes later became necrotic. However, hsp 70 immunostaining was increasingly strong in the nuclei of hepatocytes around the portal area, which did not become necrotic. These findings show that, in acute necrosis, hsp 70 seems to correlate with nuclear protection or with the transportation of some protein from the cytosol to the nucleus. Hepatocytes probably neither survive nor regenerate without hsp 70 in their nuclei.

Induction of heat shock protein and prevention of caerulein-induced pancreatitis by water-immersion stress in rats

Water-immersion stress is known to be involved in the development of hemorrhagic pancreatitis in caerulein-induced pancreatitis, when the stress is given following caerulein injection. The effects of pre-treatment with water-immersion to caerulein-induced pancreatitis were investigated in this study. 1. A 60-kDa heat shock protein was induced by pre-treatment with water-immersion stress in the pancreas. 2. Intra-peritoneal injection of caerulein (40 micrograms/kg) induced acute pancreatitis in rats without pre-treatment with water-immersion. However, when the rats were pre-treated with water-immersion, acute pancreatitis was not developed and no change of serum amylase levels was observed by i.p. injection of caerulein.

Endothelin receptor density in human hypertrophic and non-hypertrophic prostate tissue

The amount of endothelin receptors in human prostate tissue was measured by radioligand binding techniques using 125I-Endothelin -1 and -3 (125I-ET-1, -3). Specimens of the non-hypertrophy group were obtained from 6 patients who underwent total cystectomy under the diagnosis of bladder cancer and those of the hypertrophy group from 6 prostatic hypertrophy patients who underwent open prostatectomy. 125I-ET-1 bound to the prostate tissue with the KD value of 0.033 +/- 0.012 nM in the non-hypertrophy group and with the KD value of 0.035 +/- 0.012 nM in the hypertrophy group. 125I-ET-3 bound to the prostate tissue with the KD value of 0.023 +/- 0.011 nM in the non-hypertrophy group and with the KD value of 0.029 +/- 0.016 nM in the hypertrophy group. The KD values were not significantly different between the hypertrophy and non-hypertrophy groups. The KD values of 125I-ET-1 and 125I-ET-3 were similar. The Bmax values (fmol/mg protein) of 125I-ET-1 binding to the prostate tissue were 32.18 +/- 3.69 to the non-hypertrophy group and 85.66 +/- 20.65 to the hypertrophy group. The Bmax values (fmol/mg protein) of 125I-ET-3 binding to the prostate tissue were 27.48 +/- 5.25 to the non-hypertrophy group and 75.90 +/- 13.46 to the hypertrophy group. The Bmax values of both 125I-ET-1 and 125I-ET-3 were significantly higher in the hypertrophy group than in the non-hypertrophy group.(ABSTRACT TRUNCATED AT 250 WORDS)

Induction and altered localization of 90-kDa heat-shock protein in rat kidneys with cisplatin-induced acute renal failure

We purified 90-kDa heat-shock protein (HSP90) from murine brains and produced a specific antibody against the protein in a rabbit. This antibody cross-reacted with rat renal HSP90 on immunoblot analysis. Using the antibody, we observed serial immunohistochemical localizations of HSP90 in rat kidneys with cisplatin-induced acute renal failure. In normal kidneys, HSP90 was mainly localized in the cytoplasm of distal tubules and collecting ducts. Twenty-four hours after the cisplatin exposure, a rapid expression of HSP90 was observed in the cytoplasm of epithelial cells in the Henle's loops (especially at the luminal side), although there was little change in these cells on light microscopy. Degenerative changes of epithelial cells appeared in the S3 segment of proximal tubules on day 3, and epithelial cell regeneration in this portion was found from day 5. On day 5, HSP90 was markedly expressed in both the cytoplasm and the nucleus of epithelial cells in the S3 segment with a granular pattern. The induced HSP90 was then accumulated in the cytoplasm of these cells on day 7 and disappeared on day 14. Immunoblot analysis of isotonic buffer-extractable renal fractions showed that there was a rapid induction of HSP90 from day 1, and that the maximum induction of HSP90 in the extract at day 5 was 6-fold that of a control. These results suggest that HSP90 plays some role related to functional abnormalities of the Henle's loops at the luminal side, and in the regeneration of damaged cells in the S3 segment of proximal tubules, during the course of cisplatin-induced acute tubular injury.

Segmental differences in the density of autonomic receptors in dog vas deferens

In order to study the segmental difference in the density of autonomic receptors of the vas deferens, we measured the amount of adrenergic alpha 1-, alpha 2- and beta-receptors and muscarinic cholinergic receptors in the three portions (prostatic, intermediate and epididymal) of dog vas deferens using radioligand binding techniques. Saturation experiments with 3H-prazosin, 3H-yohimbine, 3H-dihydroxyalprenolol and 3H-quinuclidinyl benzilate demonstrated that three were significant amounts of adrenergic alpha 1-, alpha 2- and beta-receptors and muscarinic cholinergic receptors in the three portions of dog vas deferens. Of the three portions examined, the prostatic portion was found to have a larger amount of alpha 1-, alpha 2-receptors and muscarinic receptors, while the intermediate portion was found to have a larger amount of beta-receptors. The epididymal portion was found to have a smaller amount of autonomic receptors. These data suggest that the prostatic portion plays a more important role in the function of the dog vas deferens. It is thought that the different segments of the vas deferens have a different functional role according to the distribution of autonomic receptors.

Induction of a 60-kDa heat shock protein in rat pancreas by water-immersion stress

1. In this study, expression of a 60-kDa heat shock protein in rat pancreas was investigated before and after water-immersion stress, which has been known as an exacerbation factor of caerulein-induced pancreatitis in rats, by Western blot. 2. A 60-kDa heat shock protein increased after water-immersion stress in both soluble and insoluble fractions of the pancreas. 3. Serum amylase level and pancreas weight did not increase after water-immersion. 4. No pathologic alteration was observed in the pancreas after water-immersion.

Quantitative analysis of adrenergic alpha-1 and alpha-2 receptors in human prostatic urethral tissue

We measured the adrenergic alpha-1 and alpha-2 receptors in 3 types of prostatic tissue (prostatic urethral mucosa, prostatic adenoma and prostatic capsule) in a group of patients with benign prostatic hypertrophy (BPH) and in another group without BPH, using radioligand binding techniques. In all tissues examined, more alpha-1 and alpha-2 receptors were found in the hypertrophy group than in the other group. The increase in density of these receptors in the hypertrophy group was most marked in the prostatic adenoma. The density of alpha-1 and alpha-2 receptors was almost the same in the adenoma in both groups. The prostatic capsule and urethra in both groups contained more alpha-1 than alpha-2 receptors. Both receptors were found more in the adenoma than in the other 2 tissues in both groups. These results suggest that alpha-1 and alpha-2 receptors both play an important part in the symptoms of benign prostatic hypertrophy.

Altered localization of 73-kilodalton heat-shock protein in rat kidneys with gentamicin-induced acute tubular injury

BACKGROUND

The constitutive 73-kilodalton heat-shock protein (HSP73) has been shown to have various essential functions in cells under both normal and stress conditions. In the present study, we observed serial localizations of HSP73 in rat kidneys with gentamicin-induced acute tubular injury.

EXPERIMENTAL DESIGN

Sprague-Dawley rats received gentamicin (80 mg/kg/day) for 14 days, and developed acute proximal tubular injury. The intrarenal immunohistochemical distribution of HSP73 was examined by using a specific antibody against HSP73. In addition, HSP73 content in both isotonic buffer- and detergent-extractable renal fractions were measured by immunoblot analysis.

RESULTS

After the gentamicin exposure, HSP73 moved from the nucleus to the cytoplasm, and accumulated in granules that were considered to be expressed within enlarged lysosomes in the injured proximal tubular epithelial cells. These granules started to appear from 36 hours after the first gentamicin exposure, enlarged in size until day 12, and gradually diminished after day 18. At day 27, the HSP73 localization pattern returned to that in the normal kidney. Moreover, significantly increased HSP73 protein bands were detected by immunoblot of detergent-extractable fractions from gentamicin-treated rat kidneys at from 36 hours to day 15 after the gentamicin exposure.

CONCLUSIONS

Our findings suggest that HSP73 is rapidly induced as an insoluble form in injured lysosomes of the proximal tubular epithelial cells during gentamicin-induced acute tubular injury.

Domain structure of the 90-kDa stress protein: heparin- and antibody-binding domain

1. To understand the physiological roles of the 90-kDa stress protein (HSP90), we investigated the heparin- and antibody-binding domains of the protein. 2. For heparin-binding sites, HSP90 was digested completely with trypsin, and the digests were applied to a heparin-Sepharose column and eluted with 1.0 M NaCl, followed by 8.0 M urea. 3. Each elutant was purified by a reverse-phase C18 column. 4. Two peptides from the NaCl-eluted fraction and no peptide from the urea-eluted fraction were purified. 5. The purified peptides were sequenced by an automated peptide sequencer. 6. One of the heparin-binding sites was present between Leu-362 and Arg-365; another was present between Leu-645 and Lys-648. 7. These two peptides were basic and considerably hydrophilic. 8. For antibody-binding sites, HSP90 was mildly digested with trypsin, electrophoresed on SDS-polyacrylamide gels and transferred to PVDF membranes. 9. The four bound of the trypsin fragments could be sequenced with a peptide sequencer. 10. There was only one antibody-binding peptide, 38 kDa, starting from Pro-2. The others showed no cross-reactivity with the antibody and started from Leu-283. 11. Therefore, the epitopes of HSP90 are present between Pro-2 and Leu-282. 12. The heparin-binding sites are present from the middle region of the HSP90 molecule, and the antigen sites are at the N-terminal domain.

Physicochemical property of bovine brain 73-kDa stress protein

1. An approximately 70-kDa protein was purified from bovine brain using an ATP-Sepharose column. 2. The protein sample was found to contain two proteins (major 73 kDa and minor 72 kDa) on two-dimensional gel electrophoresis. 3. Antibodies raised against the 73- and 72-kDa proteins cross-reacted with stress-induced HSP73 and HSP72 from HeLa cells, respectively. 4. Heparin-binding peptides were obtained from trypsin digests of HSP73.