Hsp72 preserves muscle function and slows progression of severe muscular dystrophy.

Authors: Gehrig SM, van der Poel C, Sayer TA, Schertzer JD, Henstridge DC, Church JE, Lamon S, Russell AP, Davies KE, Febbraio MA, Lynch GS.
Publisher: Nature. 2012 Apr 4;484(7394):394-8.

Duchenne muscular dystrophy (DMD) is a severe and progressive muscle wasting disorder caused by mutations in the dystrophin gene that result in the absence of the membrane-stabilizing protein dystrophin. Dystrophin-deficient muscle fibres are fragile and susceptible to an influx of Ca(2+), which activates inflammatory and muscle degenerative pathways. At present there is no cure for DMD, and existing therapies are ineffective. Here we show that increasing the expression of intramuscular heat shock protein 72 (Hsp72) preserves muscle strength and ameliorates the dystrophic pathology in two mouse models of muscular dystrophy. Treatment with BGP-15 (a pharmacological inducer of Hsp72 currently in clinical trials for diabetes) improved muscle architecture, strength and contractile function in severely affected diaphragm muscles in mdx dystrophic mice. In dko mice, a phenocopy of DMD that results in severe spinal curvature (kyphosis), muscle weakness and premature death, BGP-15 decreased kyphosis, improved the dystrophic pathophysiology in limb and diaphragm muscles and extended lifespan. We found that the sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA, the main protein responsible for the removal of intracellular Ca(2+)) is dysfunctional in severely affected muscles of mdx and dko mice, and that Hsp72 interacts with SERCA to preserve its function under conditions of stress, ultimately contributing to the decreased muscle degeneration seen with Hsp72 upregulation. Treatment with BGP-15 similarly increased SERCA activity in dystrophic skeletal muscles. Our results provide evidence that increasing the expression of Hsp72 in muscle (through the administration of BGP-15) has significant therapeutic potential for DMD and related conditions, either as a self-contained therapy or as an adjuvant with other potential treatments, including gene, cell and pharmacological therapies.

BGP-15, a PARP-inhibitor, prevents imatinib-induced cardiotoxicity by activating Akt and suppressing JNK and p38 MAP kinases.

Authors: Sarszegi Z, Bognar E, Gaszner B, Kónyi A, Gallyas F Jr, Sumegi B, Berente Z.
Publisher: Mol Cell Biochem. 2012 Jun;365(1-2):129-37.

In this study, we investigate the cardiotoxic effects of the well-known cytostatic agent imatinib mesylate (Gleevec), and presented evidence for the cardioprotective effect of BGP-15 which is a novel insulin sensitizer. The cardiotoxic effect of imatinib mesylate was assessed in Langendorff rat heart perfusion system. The cardiac high-energy phosphate levels (creatine phosphate (PCr) and ATP) were monitored in situ by (31)P NMR spectroscopy. The protein oxidation, lipid peroxidation, and the activation of signaling pathways were determined from the freeze-clamped hearts. Prolonged treatment of the heart with imatinib mesylate (20 mg/kg) resulted in cardiotoxicity, which were characterized by the depletion of high-energy phosphates (PCr and ATP), and significantly increased protein oxidation and lipid peroxidation. Imatinib mesylate treatment-induced activation of MAP kinases (including ERK1/2, p38, and JNK) and the phosphorylation of Akt and GSK-3beta. BGP-15 (200 μM) prevented the imatinib mesylate-induced oxidative damages, attenuated the depletion of high-energy phosphates, altered the signaling effect of imatinib mesylate by preventing p38 MAP kinase and JNK activation, and induced the phosphorylation of Akt and GSK-3beta. The suppressive effect of BGP-15 on p38 and JNK activation could be significant because these kinases contribute to the cell death and inflammation in the isolated perfused heart.

The HSP co-inducer BGP-15 can prevent the metabolic side effects of the atypical antipsychotics.

Authors: Literáti-Nagy Z, Tory K, Literáti-Nagy B, Kolonics A, Török Z, Gombos I, Balogh G, Vígh L Jr, Horváth I, Mandl J, Sümegi B, Hooper PL, Vígh L.
Publisher: Cell Stress Chaperones. 2012 Jul;17(4):517-21.

Weight gain and dysfunction of glucose and lipid metabolism are well-known side effects of atypical antipsychotic drugs (AAPD). Here, we address the question whether a heat-shock protein (HSP) co-inducer, insulin sensitizer drug candidate, BGP-15, can prevent AAPD-induced glucose, lipid, and weight changes. We also examined how an AAPD alters HSP expression and whether BGP-15 alters that expression. Four different experiments are reported on the AAPD BGP-15 interventions in a human trial of healthy men, a rodent animal model, and an in vitro adipocyte cell culture system. Olanzapine caused rapid insulin resistance in healthy volunteers and was associated with decreased level of HSP72 in peripheral mononuclear blood cells. Both changes were restored by the administration of BGP-15. In Wistar rats, weight gain and insulin resistance induced by clozapine were abolished by BGP-15. In 3T3L1 adipocytes, clozapine increased intracellular fat accumulation, and BGP-15 inhibited this process. Taken together, our results indicate that BGP-15 inhibits multiple metabolic side effects of atypical antipsychotics, and this effect is likely to be related to its HSP co-inducing ability.

Membrane-lipid therapy in operation: the HSP co-inducer BGP-15 activates stress signal transduction pathways by remodeling plasma membrane rafts.

Authors: Gombos I, Crul T, Piotto S, Güngör B, Török Z, Balogh G, Péter M, Slotte JP, Campana F, Pilbat AM, Hunya A, Tóth N, Literati-Nagy Z, Vígh L Jr, Glatz A, Brameshuber M, Schütz GJ, Hevener A, Febbraio MA, Horváth I, Vígh L.
Publisher: PLoS One. 2011;6(12):e28818.

Aging and pathophysiological conditions are linked to membrane changes which modulate membrane-controlled molecular switches, causing dysregulated heat shock protein (HSP) expression. HSP co-inducer hydroxylamines such as BGP-15 provide advanced therapeutic candidates for many diseases since they preferentially affect stressed cells and are unlikely have major side effects. In the present study in vitro molecular dynamic simulation, experiments with lipid monolayers and in vivo ultrasensitive fluorescence microscopy showed that BGP-15 alters the organization of cholesterol-rich membrane domains. Imaging of nanoscopic long-lived platforms using the raft marker glycosylphosphatidylinositol-anchored monomeric green fluorescent protein diffusing in the live Chinese hamster ovary (CHO) cell plasma membrane demonstrated that BGP-15 prevents the transient structural disintegration of rafts induced by fever-type heat stress. Moreover, BGP-15 was able to remodel cholesterol-enriched lipid platforms reminiscent of those observed earlier following non-lethal heat priming or membrane stress, and were shown to be obligate for the generation and transmission of stress signals. BGP-15 activation of HSP expression in B16-F10 mouse melanoma cells involves the Rac1 signaling cascade in accordance with the previous observation that cholesterol affects the targeting of Rac1 to membranes. Finally, in a human embryonic kidney cell line we demonstrate that BGP-15 is able to inhibit the rapid heat shock factor 1 (HSF1) acetylation monitored during the early phase of heat stress, thereby promoting a prolonged duration of HSF1 binding to heat shock elements. Taken together, our results indicate that BGP-15 has the potential to become a new class of pharmaceuticals for use in 'membrane-lipid therapy' to combat many various protein-misfolding diseases associated with aging.

Effects of different small HSPB members on contractile dysfunction and structural changes in a Drosophila melanogaster model for Atrial Fibrillation.

Authors: Zhang D, Ke L, Mackovicova K, Van Der Want JJ, Sibon OC, Tanguay RM, Morrow G, Henning RH, Kampinga HH, Brundel BJ.
Publisher: J Mol Cell Cardiol. 2011 Sep;51(3):381-9.

The most common clinical tachycardia, Atrial Fibrillation (AF), is a progressive disease, caused by cardiomyocyte remodeling, which finally results in contractile dysfunction and AF persistence. Recently, we identified a protective role of heat shock proteins (HSPs), especially the small HSPB1 member, against tachycardia remodeling in experimental AF models. Our understanding of tachycardia remodeling and anti-remodeling drugs is currently hampered by the lack of suitable (genetic) manipulatable in vivo models for rapid screening of key targets in remodeling. We hypothesized that Drosophila melanogaster can be exploited to study tachycardia remodeling and protective effects of HSPs by drug treatments or by utilizing genetically manipulated small HSP-overexpressing strains. Tachypacing of Drosophila pupae resulted in gradual and significant cardiomyocyte remodeling, demonstrated by reduced contraction rate, increase in arrhythmic episodes and reduction in heart wall shortening, compared to normal paced pupae. Heat shock, or pre-treatment with HSP-inducers GGA and BGP-15, resulted in endogenous HSP overexpression and protection against tachycardia remodeling. DmHSP23 overexpressing Drosophilas were protected against tachycardia remodeling, in contrast to overexpression of other small HSPs (DmHSP27, DmHSP67Bc, DmCG4461, DmCG7409, and DmCG14207). (Ultra)structural evaluation of the tachypaced heart wall revealed loss of sarcomeres and mitochondrial damage which were absent in tachypaced DmHSP23 overexpressing Drosophila. In addition, tachypacing induced a significant increase in calpain activity, which was prevented in tachypaced Drosophila overexpressing DmHSP23. Tachypacing of Drosophila resulted in cardiomyocyte remodeling, which was prevented by general HSP-inducing treatments and overexpression of a single small HSP, DmHSP23. Thus, tachypaced D. melanogaster can be used as an in vivo model system for rapid identification of novel targets to combat AF associated cardiomyocyte remodeling.

Beneficial effect of the insulin sensitizer (HSP inducer) BGP-15 on olanzapine-induced metabolic disorders.

Authors: Literáti-Nagy B, Péterfai E, Kulcsár E, Literáti-Nagy Z, Buday B, Tory K, Mandl J, Sümegi B, Fleming A, Roth J, Korányi L.
Publisher: Brain Res Bull. 2010 Nov 20;83(6):340-4.

Olanzapine is a widely used atypical antipsychotic, with well known metabolic side effects such as weight gain, insulin resistance and blood glucose abnormalities. It has been previously shown in a phase II clinical trial that BGP-15, an amidoxim derivative has insulin-sensitizing effects. The aim of this study was to investigate the efficacy of BGP-15 for the treatment of olanzapine-induced metabolic side effects, in healthy volunteers. Thirty-seven (37) subjects (ages 18-55 years) with normal glucose metabolism were randomly assigned to 17 days of once-daily treatment with 400mg of BGP-15 or placebo and 5mg of olanzapine for 3 days followed by 10mg for 14 days. Total body and muscle tissue glucose utilization was determined by hyperinsulinemic-euglycemic clamp technique. As expected the 17-day olanzapine treatment provoked insulin resistance and body weight gain (p<0.05) in both groups. Administration of BGP-15 significantly reduced olanzapine-induced insulin resistance. The protective effect of BGP-15 on insulin stimulated glucose utilization had the highest magnitude in the values calculated for the muscle tissue (p=0.002). In healthy individuals BGP-15 was safe and well tolerated during the whole study period. It is suggested that BGP-15 can be a successful insulin sensitizer agent to prevent side effects of olanzapine treatment.

BGP-15 inhibits caspase-independent programmed cell death in acetaminophen-induced liver injury.

Authors: Nagy G, Szarka A, Lotz G, Dóczi J, Wunderlich L, Kiss A, Jemnitz K, Veres Z, Bánhegyi G, Schaff Z, Sümegi B, Mandl J.
Publisher: Toxicol Appl Pharmacol. 2010 Feb 15;243(1):96-103.

It has been recently shown that acute acetaminophen toxicity results in endoplasmic reticulum redox stress and an increase in cells with apoptotic phenotype in liver. Since activation of effector caspases was absent, the relevance of caspase-independent mechanisms in acetaminophen-induced programmed cell death was investigated. BGP-15, a drug with known protective actions in conditions involving redox imbalance, has been co-administered with a single sublethal dose of acetaminophen. Proapoptotic events and outcome of the injury were investigated. ER redox alterations and early ER-stress-related signaling events induced by acetaminophen, such as ER glutathione depletion, phosphorylation of eIF2alpha and JNK and induction of the transcription factor GADD153, were not counteracted by co-treatment with BGP-15. However, BGP-15 prevented AIF mitochondria-to-nucleus translocation and mitochondrial depolarization. BGP-15 co-treatment attenuated the rate of acetaminophen-induced cell death as assessed by apoptotic index and enzyme serum release. These results reaffirm that acute acetaminophen toxicity involves oxidative stress-induced caspase-independent cell death. In addition, pharmacological inhibition of AIF translocation may effectively protect against or at least delay acetaminophen-induced programmed cell death.

Improvement of insulin sensitivity by a novel drug, BGP-15, in insulin-resistant patients: a proof of concept randomized double-blind clinical trial.

Authors: Literáti-Nagy B, Kulcsár E, Literáti-Nagy Z, Buday B, Péterfai E, Horváth T, Tory K, Kolonics A, Fleming A, Mandl J, Korányi L.
Publisher: Horm Metab Res. 2009 May;41(5):374-80.

The efficacy and safety of the new drug, BGP-15, were compared with placebo in insulin-resistant patients in a 28-day dose-ranging study. Forty-seven nondiabetic patients with impaired glucose tolerance were randomly assigned to 4 weeks of treatment with 200 or 400 mg of BGP-15 or placebo. Insulin resistance was determined by hyperinsulinemic euglycemic clamp technique and homeostasis model assessment method, and beta-cell function was measured by intravenous glucose tolerance test. Each BGP-15 dose significantly increased whole body insulin sensitivity (M-1, p=0.032), total body glucose utilization (M-2, p=0.035), muscle tissue glucose utilization (M-3, p=0.040), and fat-free body mass glucose utilization (M-4, p=0.038) compared to baseline and placebo. No adverse drug effects were observed during treatment. BGP-15 at 200 or 400 mg significantly improved insulin sensitivity in insulin-resistant, nondiabetic patients during treatment compared to placebo and was safe and well-tolerated. This was the first clinical study demonstrating the insulin-sensitizing effect of a molecule, which is considered as a co-inducer of heat shock proteins.

HSP72 protects against obesity-induced insulin resistance.

Authors: Chung J, Nguyen AK, Henstridge DC, Holmes AG, Chan MH, Mesa JL, Lancaster GI, Southgate RJ, Bruce CR, Duffy SJ, Horvath I, Mestril R, Watt MJ, Hooper PL, Kingwell BA, Vigh L, Hevener A, Febbraio MA.
Publisher: Proc Natl Acad Sci U S A. 2008 Feb 5;105(5):1739-44.

Patients with type 2 diabetes have reduced gene expression of heat shock protein (HSP) 72, which correlates with reduced insulin sensitivity. Heat therapy, which activates HSP72, improves clinical parameters in these patients. Activation of several inflammatory signaling proteins such as c-jun amino terminal kinase (JNK), inhibitor of kappaB kinase, and tumor necrosis factor-alpha, can induce insulin resistance, but HSP 72 can block the induction of these molecules in vitro. Accordingly, we examined whether activation of HSP72 can protect against the development of insulin resistance. First, we show that obese, insulin resistant humans have reduced HSP72 protein expression and increased JNK phosphorylation in skeletal muscle. We next used heat shock therapy, transgenic overexpression, and pharmacologic means to overexpress HSP72 either specifically in skeletal muscle or globally in mice. Herein, we show that regardless of the means used to achieve an elevation in HSP72 protein, protection against diet- or obesity-induced hyperglycemia, hyperinsulinemia, glucose intolerance, and insulin resistance was observed. This protection was tightly associated with the prevention of JNK phosphorylation. These findings identify an essential role for HSP72 in blocking inflammation and preventing insulin resistance in the context of genetic obesity or high-fat feeding.

The chaperone co-inducer BGP-15 alleviates ventilation-induced diaphragm dysfunction.

Authors: Salah H, Li M, Cacciani N, Gastaldello S, Ogilvie H, Akkad H, Namuduri AV, Morbidoni V, Artemenko KA, Balogh G, Martinez-Redondo V, Jannig P, Hedström Y, Dworkin B, Bergquist J, Ruas J, Vigh L, Salviati L, Larsson L.
Publisher: Sci Transl Med. 2016 Aug 3;8(350):350ra103.

Ventilation-induced diaphragm dysfunction (VIDD) is a marked decline in diaphragm function in response to mechanical ventilation, which has negative consequences for individual patients' quality of life and for the health care system, but specific treatment strategies are still lacking. We used an experimental intensive care unit (ICU) model, allowing time-resolved studies of diaphragm structure and function in response to long-term mechanical ventilation and the effects of a pharmacological intervention (the chaperone co-inducer BGP-15). The marked loss of diaphragm muscle fiber function in response to mechanical ventilation was caused by posttranslational modifications (PTMs) of myosin. In a rat model, 10 days of BGP-15 treatment greatly improved diaphragm muscle fiber function (by about 100%), although it did not reverse diaphragm atrophy. The treatment also provided protection from myosin PTMs associated with HSP72 induction and PARP-1 inhibition, resulting in improvement of mitochondrial function and content. Thus, BGP-15 may offer an intervention strategy for reducing VIDD in mechanically ventilated ICU patients.