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Dow LF, Case AM, Paustian MP, Pinkerton BR, Simeon P, Trippier PC. The evolution of small molecule enzyme activators. RSC Med Chem 2023; 14:2206-2230. [PMID: 37974956 PMCID: PMC10650962 DOI: 10.1039/d3md00399j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/20/2023] [Indexed: 11/19/2023] Open
Abstract
There is a myriad of enzymes within the body responsible for maintaining homeostasis by providing the means to convert substrates to products as and when required. Physiological enzymes are tightly controlled by many signaling pathways and their products subsequently control other pathways. Traditionally, most drug discovery efforts focus on identifying enzyme inhibitors, due to upregulation being prevalent in many diseases and the existence of endogenous substrates that can be modified to afford inhibitor compounds. As enzyme downregulation and reduction of endogenous activators are observed in multiple diseases, the identification of small molecules with the ability to activate enzymes has recently entered the medicinal chemistry toolbox to afford chemical probes and potential therapeutics as an alternative means to intervene in diseases. In this review we highlight the progress made in the identification and advancement of non-kinase enzyme activators and their potential in treating various disease states.
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Affiliation(s)
- Louise F Dow
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Alfie M Case
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Megan P Paustian
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Braeden R Pinkerton
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Princess Simeon
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
| | - Paul C Trippier
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha NE 68106 USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center Omaha NE 68106 USA
- UNMC Center for Drug Discovery, University of Nebraska Medical Center Omaha NE 68106 USA
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Lesire L, Leroux F, Deprez-Poulain R, Deprez B. Insulin-Degrading Enzyme, an Under-Estimated Potential Target to Treat Cancer? Cells 2022; 11:cells11071228. [PMID: 35406791 PMCID: PMC8998118 DOI: 10.3390/cells11071228] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 02/04/2023] Open
Abstract
Insulin-degrading enzyme (IDE) is a multifunctional protease due to the variety of its substrates, its various cellular locations, its conservation between species and its many non-proteolytic functions. Numerous studies have successfully demonstrated its implication in two main therapeutic areas: metabolic and neuronal diseases. In recent years, several reports have underlined the overexpression of this enzyme in different cancers. Still, the exact role of IDE in the physiopathology of cancer remains to be elucidated. Known as the main enzyme responsible for the degradation of insulin, an essential growth factor for healthy cells and cancer cells, IDE has also been shown to behave like a chaperone and interact with the proteasome. The pharmacological modulation of IDE (siRNA, chemical compounds, etc.) has demonstrated interesting results in cancer models. All these results point towards IDE as a potential target in cancer. In this review, we will discuss evidence of links between IDE and cancer development or resistance, IDE's functions, catalytic or non-catalytic, in the context of cell proliferation, cancer development and the impact of the pharmacomodulation of IDE via cancer therapeutics.
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Zhang T, Jiang Q, Xu F, Zhang R, Liu D, Guo D, Wu J, Wen Y, Wang X, Jiang W, Bi H. Alternation of Resting-State Functional Connectivity Between Visual Cortex and Hypothalamus in Guinea Pigs With Experimental Glucocorticoid Enhanced Myopia After the Treatment of Electroacupuncture. Front Neuroinform 2021; 14:579769. [PMID: 33519409 PMCID: PMC7838498 DOI: 10.3389/fninf.2020.579769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 12/07/2020] [Indexed: 12/12/2022] Open
Abstract
Excessive glucocorticoids (GC) may lead to the aggravation of several basic diseases including myopia, due to plasma hormone imbalances associated with the hypothalamic–pituitary–adrenal axis (HPAA). Electroacupuncture (EA) is an effective therapeutic method to treat many diseases, although it remains unclear whether EA at acupoints on the foot or back would be effective in treating eye diseases. It was recently found that visual cortex activity for responses to visual stimuli with spatial frequency and resting-state functional connectivity (FC) between the supramarginal gyrus and rostrolateral prefrontal cortex was significantly reduced in patients with high myopia. The present study aims to investigate the role of the alternation of resting-state FC among the bilateral visual cortex and hypothalamus in exerting anti-myopia effects of EA in GC-enhanced lens-induced myopic (LIM) guinea pigs such that the mechanisms of EA to treat GC-enhanced myopia at Shenshu (BL23) acupoints can be probed. To confirm the effects of EA, ocular parameters including axial length and GC-associated physiological parameters such as animal appearance, behavior, bodyweight, and levels of four HPAA-associated plasma hormones [free triiodothyronine (FT3), free thyroxine (FT4), estradiol (E2), and testosterone (T)] were also collected. Increased resting-state FC between the left and right visual cortex was detected in GC-enhanced lens-induced myopic guinea pigs with EA at BL23 acupoints (LIM+GC+EA) guinea pigs compared to GC-enhanced lens-induced myopic guinea pigs with EA at sham acupoints (LIM+GC+Sham) guinea pigs, as well as suppressed myopia and recovery of symptoms initially caused by overdose of GC. Recovered symptoms included improved animal appearance, behavior, bodyweight, and HPAA-associated plasma hormone levels were observed after 4 weeks of EA treatment. In contrast, the LIM+GC+Sham group showed decreased FC with elongation of axial length for myopization as compared to the control group and LIM group and exhibited a deterioration in physiological parameters including reduced body weight and balance disruption in the four measured HPAA-associated plasma hormones. Our findings suggest that EA could effectively treat GC-enhanced myopia by increasing resting-state FC between the left and right visual cortices, which may be pivotal to further understanding the application and mechanisms of EA in treating GC-enhanced myopia.
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Affiliation(s)
- Tao Zhang
- The First College of Clinical Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Qian Jiang
- Department of Ophthalmology and Optometry, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Furu Xu
- Department of Ophthalmology and Optometry, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Ruixue Zhang
- Department of Ophthalmology and Optometry, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Dezheng Liu
- Department of Ophthalmology and Optometry, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Dadong Guo
- Shandong Province Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Therapy of Ocular Disease, Eye Institute of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Jianfeng Wu
- Department of Ophthalmology and Optometry, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Ying Wen
- Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xingrong Wang
- Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Wenjun Jiang
- Shandong Province Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Therapy of Ocular Disease, Eye Institute of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Hongsheng Bi
- Shandong Province Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Therapy of Ocular Disease, Eye Institute of Shandong University of Traditional Chinese Medicine, Jinan, China
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4
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Takayama K, Fujiwara K, Inoue S. Amyloid precursor protein, an androgen‐regulated gene, is targeted by RNA‐binding protein PSF/SFPQ in neuronal cells. Genes Cells 2019; 24:719-730. [DOI: 10.1111/gtc.12721] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 09/09/2019] [Accepted: 09/14/2019] [Indexed: 01/07/2023]
Affiliation(s)
- Ken‐ichi Takayama
- Department of Systems Aging Science and Medicine Tokyo Metropolitan Institute of Gerontology Tokyo Japan
| | - Kyoko Fujiwara
- Department of Medicine Nihon University School of Medicine Tokyo Japan
- Department of Anatomy Nihon University School of Dentistry Tokyo Japan
| | - Satoshi Inoue
- Department of Systems Aging Science and Medicine Tokyo Metropolitan Institute of Gerontology Tokyo Japan
- Division of Gene Regulation and Signal Transduction Research Center for Genomic Medicine Saitama Medical University Hidaka Saitama Japan
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Lei Y, Renyuan Z. Effects of Androgens on the Amyloid-β Protein in Alzheimer's Disease. Endocrinology 2018; 159:3885-3894. [PMID: 30215697 DOI: 10.1210/en.2018-00660] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 09/06/2018] [Indexed: 12/24/2022]
Abstract
Age-related androgen depletion has been implicated in compromised neuroprotection and is involved in the pathogenesis of neurodegenerative disease, including Alzheimer's disease (AD), the leading cause of dementia. Emerging data revealed that reduction of both serum and brain androgen levels in males is associated with increased amyloid-β (Aβ) accumulation, a putative cause of AD. It has been demonstrated that androgens can function as the endogenous negative regulators of Aβ. However, the mechanisms by which androgens regulate Aβ production, degradation, and clearance, as well as the Aβ-induced pathological process in AD, are still elusive. This review emphasizes the contributions of androgen to Aβ metabolism and toxicity in AD and thus may provide novel strategies for prevention and therapeutics.
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Affiliation(s)
- Yang Lei
- Department of Urology, Jing'an District Central Hospital, Fudan University, Shanghai, China
| | - Zhou Renyuan
- Department of Urology, Jing'an District Central Hospital, Fudan University, Shanghai, China
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Asih PR, Tegg ML, Sohrabi H, Carruthers M, Gandy SE, Saad F, Verdile G, Ittner LM, Martins RN. Multiple Mechanisms Linking Type 2 Diabetes and Alzheimer's Disease: Testosterone as a Modifier. J Alzheimers Dis 2018; 59:445-466. [PMID: 28655134 DOI: 10.3233/jad-161259] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Evidence in support of links between type-2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) has increased considerably in recent years. AD pathological hallmarks include the accumulation of extracellular amyloid-β (Aβ) and intracellular hyperphosphorylated tau in the brain, which are hypothesized to promote inflammation, oxidative stress, and neuronal loss. T2DM exhibits many AD pathological features, including reduced brain insulin uptake, lipid dysregulation, inflammation, oxidative stress, and depression; T2DM has also been shown to increase AD risk, and with increasing age, the prevalence of both conditions increases. In addition, amylin deposition in the pancreas is more common in AD than in normal aging, and although there is no significant increase in cerebral Aβ deposition in T2DM, the extent of Aβ accumulation in AD correlates with T2DM duration. Given these similarities and correlations, there may be common underlying mechanism(s) that predispose to both T2DM and AD. In other studies, an age-related gradual loss of testosterone and an increase in testosterone resistance has been shown in men; low testosterone levels can also occur in women. In this review, we focus on the evidence for low testosterone levels contributing to an increased risk of T2DM and AD, and the potential of testosterone treatment in reducing this risk in both men and women. However, such testosterone treatment may need to be long-term, and would need regular monitoring to maintain testosterone at physiological levels. It is possible that a combination of testosterone therapy together with a healthy lifestyle approach, including improved diet and exercise, may significantly reduce AD risk.
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Affiliation(s)
- Prita R Asih
- Department of Anatomy, Dementia Research Unit, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.,KaRa Institute of Neurological Diseases, Sydney, NSW, Australia
| | - Michelle L Tegg
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - Hamid Sohrabi
- School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia.,Australian Alzheimer's Research Foundation Perth, WA, Australia.,Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia.,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Perth, WA, Australia
| | | | - Samuel E Gandy
- Departments of Neurology and Psychiatry and the Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, One Gustave L Levy Place, New York, NY, USA
| | - Farid Saad
- Bayer Pharma AG, Global Medical Affairs Andrology, Berlin, Germany.,Gulf Medical University School of Medicine, Ajman, UAE
| | - Giuseppe Verdile
- Australian Alzheimer's Research Foundation Perth, WA, Australia.,School of Biomedical Sciences, Curtin University of Technology, Bentley, WA, Australia
| | - Lars M Ittner
- Department of Anatomy, Dementia Research Unit, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Ralph N Martins
- KaRa Institute of Neurological Diseases, Sydney, NSW, Australia.,School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia.,Australian Alzheimer's Research Foundation Perth, WA, Australia.,Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia.,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Perth, WA, Australia
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Duarte AC, Hrynchak MV, Gonçalves I, Quintela T, Santos CRA. Sex Hormone Decline and Amyloid β Synthesis, Transport and Clearance in the Brain. J Neuroendocrinol 2016; 28. [PMID: 27632792 DOI: 10.1111/jne.12432] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/12/2016] [Accepted: 09/12/2016] [Indexed: 12/15/2022]
Abstract
Sex hormones (SH) are essential regulators of the central nervous system. The decline in SH levels along with ageing may contribute to compromised neuroprotection and set the grounds for neurodegeneration and cognitive impairments. In Alzheimer's disease, besides other pathological features, there is an imbalance between amyloid β (Aβ) production and clearance, leading to its accumulation in the brain of older subjects. Aβ accumulation is a primary cause for brain inflammation and degeneration, as well as concomitant cognitive decline. There is mounting evidence that SH modulate Aβ production, transport and clearance. Importantly, SH regulate most of the molecules involved in the amyloidogenic pathway, their transport across brain barriers for elimination, and their degradation in the brain interstitial fluid. This review brings together data on the regulation of Aβ production, metabolism, degradation and clearance by SH.
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Affiliation(s)
- A C Duarte
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
| | - M V Hrynchak
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
| | - I Gonçalves
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
| | - T Quintela
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
| | - C R A Santos
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
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Camberos MDC, Pérez AA, Passicot GA, Martucci LC, Wanderley MI, Udrisar DP, Cresto JC. II - Insulin processing in mitochondria. J Bioenerg Biomembr 2016; 48:469-482. [PMID: 27796771 DOI: 10.1007/s10863-016-9682-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 10/12/2016] [Indexed: 11/29/2022]
Abstract
Our objective was to know how insulin is processing in mitochondria; if IDE is the only participant in mitochondrial insulin degradation and the role of insulin degradation on IDE accumulation in mitoplasts. Mitochondria and its fractions were isolated as described by Greenwalt. IDE was purified and detected in immunoblot with specific antibodies. High insulin degradation was obtained through addition to rat's diet of 25 g/rat of apple and 10 g/rat of hard-boiled eggs, 3 days a week. Mitochondrial insulin degradation was assayed with 5 % TCA, insulin antibody or Sephadex G50 chromatography. Degradation was also assayed 60 min at 37 °C in mitochondrial fractions (IMS and Mx) with diet or not and without IDE. Degradation in fractions precipitated with ammonium sulfates (60-80 %) were studied after mitochondrial insulin incubation (1 ng. insulin during 15 min, at 30 °C) or with addition of 2.5 mM ATP. Supplementary diet increased insulin degradation. High insulin did not increase mitoplasts accumulation and did not decrease mitochondrial degradation. High insulin and inhibition of degradation evidence insulin competition for a putative transport system. Mitochondrial incubation with insulin increased IDE in matrix as observed in immunoblot. ATP decreased degradation in Mx and increased it in IMS. Chromatography of IMS demonstrated an ATP-dependent protease that degraded insulin, similar to described by Sitte et al. Mitochondria participate in insulin degradation and the diet increased it. High insulin did not accomplish mitochondrial decrease of degradation or its accumulation in mitoplasts. Mitochondrial incubation with insulin increased IDE in matrix. ATP suggested being a regulator of mitochondrial insulin degradation.
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Affiliation(s)
- María Del Carmen Camberos
- Endocrinology Research Center "Dr. Cesar Bergada" (CEDIE-CONICET), Endocrinology Division, Children Hospital. R. Gutierrez, Gallo 1330 (C1425), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina.
| | - Adriana A Pérez
- Department Genetic and Evolution, School of Natural and Exact Sciences, University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Gisel A Passicot
- Endocrinology Research Center "Dr. Cesar Bergada" (CEDIE-CONICET), Endocrinology Division, Children Hospital. R. Gutierrez, Gallo 1330 (C1425), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Lucía C Martucci
- Endocrinology Research Center "Dr. Cesar Bergada" (CEDIE-CONICET), Endocrinology Division, Children Hospital. R. Gutierrez, Gallo 1330 (C1425), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - María I Wanderley
- Laboratory of Endocrinology and Metabolism, Department of Physiology and Pharmacology, University of Pernambuco, Recife, Pernambuco, Brazil
| | - Daniel P Udrisar
- Laboratory of Endocrinology and Metabolism, Department of Physiology and Pharmacology, University of Pernambuco, Recife, Pernambuco, Brazil
| | - Juan C Cresto
- Endocrinology Research Center "Dr. Cesar Bergada" (CEDIE-CONICET), Endocrinology Division, Children Hospital. R. Gutierrez, Gallo 1330 (C1425), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
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Del Carmen Camberos M, Cao G, Wanderley MI, Udrisar DP, Cresto JC. I - insulin transfer to mitochondria. J Bioenerg Biomembr 2014; 46:357-70. [PMID: 25104045 DOI: 10.1007/s10863-014-9563-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/02/2014] [Indexed: 10/24/2022]
Abstract
The aim of this study was to determine if insulin is transferred to mitoplasts by insulin-degrading enzyme (IDE).Hepatic mitochondria were isolated and controlled by electron microscopy. IDE was obtained from rats muscle by successive chromatography steps. Insulin accumulation in mitoplasts and outer membrane + intermembrane space (OM + IMS) was studied with (125)I-insulin. Mitochondrial insulin accumulation and degradation was assayed with Sephadex G50 chromatography, insulin antibody and 5 % TCA. Mitoplasts and OM + IMS were isolated with digitonin. Insulin accumulation was studied at 25 °C at different times, without or with IDE, Bacitracin, 2,4-dinitrophenol, apyrase or sodium succinate + adenosine diphosphate. Insulin accumulation in mitoplasts and OM + IMS after mitochondrial cross-linking was studied with electrophoresis in SDS-PAGE, immunoblots of IDE, insulin or TIM23 (inner mitochondrial transporter) and autoradiography.The studies showed that addition of IDE increased insulin transfer from OM + IMS to mitoplasts, and the insulin accumulation in mitoplast was IDE dependent. Bacitracin and 2,4-dinitrophenol decreased this transfer. The [Insulin-IDE] complex and [Mitoplasts] was studied as a bimolecular reaction following a second order reaction. The constant "k" (liter.mol⁻¹ s⁻¹) showed that IDE increased and Bacitracin or 2,4-dinitrophenol decreased the velocity of insulin transfer. SDS-PAGE and immunoblots studies showed bands and radioactivity coincident with IDE, insulin and TIM23. Non degraded insulin was demonstrated in immunoblot after IDE immunoprecipitation from mitoplasts. Confocal studies showed mitochondrial colocalization of IDE and insulin.The results showed that insulin at 25 °C were transferred from OM + IMS to mitoplasts by IDE or that the enzyme facilitates this transfer, and they reach the matrix together.
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Affiliation(s)
- María Del Carmen Camberos
- Endocrinology Research Center (CEDIE-CONICET) Children Hospital "R. Gutiérrez", Gallo 1330, 1425, Ciudad de Buenos Aires, Argentina
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Costa MM, Violato NM, Taboga SR, Góes RM, Bosqueiro JR. Reduction of insulin signalling pathway IRS-1/IRS-2/AKT/mTOR and decrease of epithelial cell proliferation in the prostate of glucocorticoid-treated rats. Int J Exp Pathol 2012; 93:188-95. [PMID: 22583132 DOI: 10.1111/j.1365-2613.2012.00817.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Previous studies by our research group using a model of insulin resistance induced by dexamethasone (DEX) showed that in the rat ventral prostate there was epithelial and smooth muscle cell atrophy and there were also alterations in fibroblasts. Proteins of the insulin signalling pathway are known to be very important for cell proliferation and development. Thus, we investigated the insulin signalling pathway and epithelial proliferation in the rat ventral prostate in this model and correlated the findings with expression of glucocorticoid (GR) and androgen (AR) receptors. Insulin resistance was induced in adult male Wistar rats by injection of DEX (1 mg/kg, ip for 5 consecutive days), whereas control (CTL) rats received saline. DEX treatment resulted in a significant decrease in body weight, but not in prostate weight. Reductions in insulin receptor 1 (IRS-1) (CTL 1.11 ± 0.06; DEX 0.85 ± 0.03), IRS-2 (CTL 0.95 ± 0.05; DEX 0.49 ± 0.04), AKT (CTL 0.98 ± 0.03; DEX 0.78 ± 0.02), mammalian target of rapamycin (mTOR; CTL 0.65 ± 0.08; DEX 0.22 ± 0.05), GR (CTL 1.30 ± 0.09; DEX 0.57 ± 0.10) and AR (CTL 1.83 ± 0.16; DEX 0.55 ± 0.08) protein levels were observed in the prostate of DEX-treated rats. The expression of the IRα-subunit, phosphoinositide 3-kinase, p-AKT, p70(S6K) , extracellular signal-regulated kinase (ERK) and p-ERK was not altered. The frequency of AR-positive cells in the epithelium of the prostate decreased in the glucocorticoid-treated group, and the intensity of the reaction for this receptor in the cell nuclei was lower in this group. Furthermore, the treatment with DEX reduced the frequency of proliferating cell nuclear antigen-positive (PCNA) cells 30-fold. This study suggests that the reduction in the insulin signalling pathway proteins IRS-1/IRS-2/AKT/mTOR in the prostate of DEX-treated rats may be associated with the morphological alterations observed previously.
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Affiliation(s)
- Maitê M Costa
- Department of Physical Education, Faculty of Sciences, São Paulo State University-Unesp, Bauru, São Paulo, Brazil
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