bims-glecem 2022-05-29 papers

bims-glecem

Biomed News

on Glycogen metabolism in exercise, cancer and energy metabolism

Issue of 2022–05–29
thirteen papers selected by
Dipsikha Biswas, Københavns Universitet

Clinical characteristics and long-term outcomes of patients with glycogen storage disease type 1b: a retrospective multi-center experience in Poland.
Atypical infantile-onset Pompe disease with good prognosis from mainland China: A case report.
Characterization of a novel type of glycogen-degrading amylopullulanase from Lactobacillus crispatus.
Effects of Moderate-Intensity Physical Training on Skeletal Muscle Substrate Transporters and Metabolic Parameters of Ovariectomized Rats.
Carbohydrate Metabolism Parameters of Adult Glial Neoplasms According to Immunohistochemical Profile.
Fimasartan Ameliorates Deteriorations in Glucose Metabolism in a High Glucose State by Regulating Skeletal Muscle and Liver Cells.
Glycogen kinase 3 inhibitor nanoformulation as an alternative strategy to inhibit PD-1 immune checkpoint.
Long-term Safety and Efficacy of Avalglucosidase Alfa in Patients With Late-Onset Pompe Disease.
BNIP3 is involved in muscle fiber atrophy in Late-Onset Pompe Disease patients.
Expression of a constitutively active insulin receptor in Drosulfakinin (Dsk) neurons regulates metabolism and sleep in Drosophila.
Glucocorticoid Receptor β Overexpression Has Agonist-Independent Insulin-Mimetic Effects on HepG2 Glucose Metabolism.
GSK3β palmitoylation mediated by ZDHHC4 promotes tumorigenicity of glioblastoma stem cells in temozolomide-resistant glioblastoma through the EZH2-STAT3 axis.
Long-term treatment with chloroquine increases lifespan in middle-aged male mice possibly via autophagy modulation, proteasome inhibition and glycogen metabolism.

Pediatr Endocrinol Diabetes Metab. 2022 May 27. pii: 46999. [Epub ahead of print]

Clinical characteristics and long-term outcomes of patients with glycogen storage disease type 1b: a retrospective multi-center experience in Poland.

Magdalena Kaczor, Dorota Wesół-Kucharska, Milena Greczan, Karolina Kierus, Łukasz Kałużny, Monika Duś-Żuchowska, Ewa Ehmke Vel Emczyńska-Seliga, Elżbieta Ciara, Janusz Książyk, Dariusz Rokicki.

  Glycogen storage disease type 1b (GSD 1b) is an inherited metabolic defect caused by a deficiency of microsomal glucose-6-phosphate (G6P) transport protein across the endoplasmic reticulum membrane. Patients with GSD 1b have hypoglycemia episodes, lactate acidosis, hypertriglyceridemia, hypercholesterolemia, hyperuricemia, neutropenia and in imaging studies hepatomegaly and/or nephromegaly. The primary goals of treatment are to maintain proper blood glucose levels and to increase the number of properly functioning neutrophils. The aim of the study was a retrospective analysis of the clinical picture and treatment results of pediatric patients with type 1b glycogen storage disease from Poland. The study included 13 patients from 3 clinical centers, with a median age at diagnosis as 5 months. In 11/13 patients, the diagnosis was confirmed by molecular test, by the presence of pathogenic variants on both alleles of the SLC37A4 gene. Ten out of 13 patients developed the first symptoms in the form of severe infection (sepsis and/or pneumonia) already in the neonatal-infant period. A hypoglycemia episode was observed before diagnosis in 8/13 patients, of which 4/8 patients presented symptoms in the form of generalized relaxation and/or seizures. Two patients developed hypertension, and 4/13 required long-term treatment of inflammatory bowel disease.

Keywords:   SLC37A4; filgrastim; glycogenosis 1b; inflammatory bowel disease.; neutropenia; glycogen storage disease type 1b

DOI:  https://doi.org/10.5114/pedm.2022.116115
World J Clin Cases. 2022 Apr 06. 10(10): 3278-3283

Atypical infantile-onset Pompe disease with good prognosis from mainland China: A case report.

Ying Zhang, Cheng Zhang, Jian-Bo Shu, Fang Zhang.

   BACKGROUND: Pompe disease has a broad disease spectrum, including infantile-onset Pompe disease (IOPD) and late-onset Pompe disease (LOPD) forms. It is a type of glycogen storage disorder belonging to autosomal recessive genetic disease, for an estimated incidence of 1/40000 among the neonatal population. In severe cases, the natural course is characterized by death due to cardiopulmonary failure in the first year after birth. However, the clinical outcomes have improved since the emergence of enzyme replacement therapy (ERT) was widely used.
CASE SUMMARY: The reported female case in China was an atypical IOPD, which demonstrates an unusual presentation of glycogen accumulation syndrome type II without obvious skeletal muscle involvement, and reviewed physical examination, biochemical examinations, chest radiograph, and acid α-glucosidase (GAA) mutation analysis. After 4-mo specific ERT, the case received 12-mo follow-up. Moreover, the patient has obtained a very good prognosis under ERT.
CONCLUSION: For the atypical IOPD patients, early diagnosis and treatment may contribute to good prognosis.

Keywords:  Case report; Enzyme replacement therapy; Infantile-onset Pompe disease; Pompe disease; Rare genetic disease

DOI:  https://doi.org/10.12998/wjcc.v10.i10.3278
Appl Microbiol Biotechnol. 2022 May 25.

Characterization of a novel type of glycogen-degrading amylopullulanase from Lactobacillus crispatus.

Jie Zhang, Lili Li, Tong Zhang, Jin Zhong.

  Glycogen is one of the major carbohydrates utilized by the human vaginal microbiota, which is commonly dominated by Lactobacillus, especially L. crispatus. An in silico analysis predicted that a type I pullulanase was involved in glycogen degradation in L. crispatus. The biochemical and genetic properties of the pullulanase still need to be determined. Here, we de novo identified the glycogen (Glg)-utilization enzyme (named GlgU) from L. crispatus through a biochemical assay. GlgU was optimally active at acidic pH, approximately 4.0 ~ 4.5, and was able to hydrolyze glycogen into low-molecular-weight malto-oligosaccharides. Actually, GlgU was a type II pullulanase (amylopullulanase) with just one catalytic domain that possessed substrate specificity toward both α-1,4 and α-1,6-glucosidic bonds. Phylogenetically, GlgU was obviously divergent from the known amylases and pullulanases (including amylopullulanases) in lactobacilli. In addition, we confirmed the catalytic activity of glgU in a nonglycogen-utilizing lactobacilli strain, demonstrating the essential role of glgU in glycogen metabolism. Overall, this study characterized a novel type of amylopullulanases, contributing to the knowledge of the glycogen utilization mechanism of the dominant species of human vaginal microbiota. KEY POINTS: • GlgU was a type II pullulanase, not a type I pullulanase predicted before. • GlgU was able to completely hydrolyze glycogen into malto-oligosaccharides. • GlgU played a key role in the metabolism of extracellular glycogen.

Keywords:  Amylopullulanases; Glycogen degradation; Lactobacillus crispatus; The vaginal microbiota

DOI:  https://doi.org/10.1007/s00253-022-11975-2
Metabolites. 2022 Apr 29. pii: 402. [Epub ahead of print]12(5):

Effects of Moderate-Intensity Physical Training on Skeletal Muscle Substrate Transporters and Metabolic Parameters of Ovariectomized Rats.

Taciane Maria Melges Pejon, Pedro Paulo Menezes Scariot, Heloísa Sobreiro Selistre-de-Araujo, Claudio Alexandre Gobatto, Anabelle Silva Cornachione, Wladimir Rafael Beck.

  A deficit of estrogen is associated with energy substrate imbalance, raising the risk of metabolic diseases. Physical training (PT) is a potent metabolic regulator through oxidation and storage of substrates transported by GLUT4 and FAT CD36 in skeletal muscle. However, little is known about the effects of PT on these carriers in an estrogen-deficit scenario. Thus, the aim of this study was to determine the influence of 12 weeks of PT on metabolic variables and GLUT4 and FAT CD36 expression in the skeletal muscle of animals energetically impaired by ovariectomy (OVX). The trained animals swam 30 min/day, 5 days/week, at 80% of the critical load intensity. Spontaneous physical activity was measured biweekly. After training, FAT CD36 and GLUT4 expressions were quantified by immunofluorescence in the soleus, as well as muscular glycogen and triglyceride of the soleus, gluteus maximus and gastrocnemius. OVX significantly reduced FAT CD36, GLUT4 and spontaneous physical activity (p < 0.01), while PT significantly increased FAT CD36, GLUT4 and spontaneous physical activity (p < 0.01). PT increased soleus glycogen, and OVX decreased muscular triglyceride of gluteus maximus. Therefore, OVX can cause energy disarray through reduction in GLUT4 and FAT CD36 and their muscle substrates and PT prevented these metabolic consequences, masking ovarian estrogen's absence.

Keywords:  FAT CD36; GLUT4; carbohydrate metabolism; energetic balance; estrogen; hypoestrogenism; intermediary metabolism; lipid metabolism; physical exercise

DOI:  https://doi.org/10.3390/metabo12050402
Biomedicines. 2022 Apr 27. pii: 1007. [Epub ahead of print]10(5):

Carbohydrate Metabolism Parameters of Adult Glial Neoplasms According to Immunohistochemical Profile.

Larisa Obukhova, Olga Nikiforova, Claudia Kontorshchikova, Igor Medyanik, Natalya Orlinskaya, Artem Grishin, Michael Kontorshchikov, Natalya Shchelchkova.

  This research aimed to investigate the interrelationship of carbohydrate metabolism parameters and immunohistochemical characteristics of glial tumors. Tumor tissue, peritumoral area, and adjacent noncancerous tissue fragments of 20 patients with gliomas of varying degrees of anaplasia were analyzed. The greatest differences in the carbohydrate metabolism compared to adjacent noncancerous tissues were identified in the tumor tissue: reduction in the levels of lactate and glycogen synthase kinase-3β. Significant differences with adjacent noncancerous tissues for the peritumoral zone were not found. The activity of the carbohydrate metabolism enzymes was different depending on the immunohistochemical glioma profile, especially from Ki 67 level. Bioinformatic analysis of the interactions of immunohistochemical markers of gliomas and carbohydrate metabolism enzymes using the databases of STRING, BioGrid, and Signor revealed the presence of biologically significant interactions with glycogen synthase kinase 3β, hexokinase, glucose-6-phosphate dehydrogenase, and transketolase. The established interconnection of glycolysis with methylation of the promoter of O-6-methylguanine-DNA-methyltransferase (MGMT) of gliomas can be used to increase chemotherapy efficiency.

Keywords:  IDH1; Ki 67; MGMT; glucose-6-phosphate dehydrogenase; hexokinase; kinase of glycogen synthase 3β; molecular genetic markers of gliomas; p53; peritumoral zone; transketolase

DOI:  https://doi.org/10.3390/biomedicines10051007
Yonsei Med J. 2022 Jun;63(6): 530-538

Fimasartan Ameliorates Deteriorations in Glucose Metabolism in a High Glucose State by Regulating Skeletal Muscle and Liver Cells.

Yoo Na Jang, Yong Jik Lee, Yoon Mi Han, Hyun Min Kim, Hong Seog Seo, Ji Hoon Jeong, Seung Yeon Park, Tae Woo Jung.

   PURPOSE: Since diabetes and hypertension frequently occur together, it is thought that these conditions may have a common pathogenesis. This study was designed to evaluate the anti-diabetic function of the anti-hypertensive drug fimasartan on C2C12 mouse skeletal muscle and HepG2 human liver cells in a high glucose state.
MATERIALS AND METHODS: The anti-diabetic effects and mechanism of fimasartan were identified using Western blot, glucose uptake tests, oxygen consumption rate (OCR) analysis, adenosine 5'-triphosphate (ATP) enzyme-linked immunosorbent assay (ELISA), and immunofluorescence staining for diabetic biomarkers in C2C12 cells. Protein biomarkers for glycogenolysis and glycogenesis were evaluated by Western blotting and ELISA in HepG2 cells.
RESULTS: The protein levels of phosphorylated 5' adenosine monophosphate-activated protein kinase (p-AMPK), p-AKT, insulin receptor substrate-1 (IRS-1), and glucose transporter type 4 (Glut4) were elevated in C2C12 cells treated with fimasartan. These increases were reversed by peroxisome proliferator-activated receptor delta (PPARδ) antagonist. ATP, OCR, and glucose uptake were increased in cells treated with 200 µM fimasartan. Protein levels of glycogen phosphorylase, glucose synthase, phosphorylated glycogen synthase, and glycogen synthase kinase-3 (GSK-3) were decreased in HepG2 cells treated with fimasartan. However, these effects were reversed following the addition of the PPARδ antagonist GSK0660.
CONCLUSION: In conclusion, fimasartan ameliorates deteriorations in glucose metabolism as a result of a high glucose state by regulating PPARδ in skeletal muscle and liver cells.

Keywords:  Fimasartan; PPARδ; angiotensin II type 1 receptor blocker; glucose metabolism

DOI:  https://doi.org/10.3349/ymj.2022.63.6.530
Int J Pharm. 2022 May 22. pii: S0378-5173(22)00400-8. [Epub ahead of print] 121845

Glycogen kinase 3 inhibitor nanoformulation as an alternative strategy to inhibit PD-1 immune checkpoint.

Parisa Badiee, Michelle F Maritz, Benjamin Thierry.

  Immune checkpoint inhibition with antibodies targeting the programmed cell death-1 (PD-1) pathway is a frontline cancer immunotherapy. Driven by the limited response rates and high off-target toxicity associated to monoclonal antibodies, small molecule inhibitors of PD-1 are under active investigation. Glycogen synthase kinase 3 (GSK3) is an up-stream regulator of PD-1 and small molecule GSK3 inhibitors have been shown to effectively reduce T-cell expression of PD-1 receptors. Towards harnessing the potent anticancer effects of GSK3 inhibition, we report here on the development of a nanoformulation within PEG-PLGA nanoparticles of the small molecule GSK3 inhibitor SB415286. The formulation physicochemical properties were optimised using a novel 3D printed microfluidic nanoprecipitation device and a hydrophobic ion pairing approach was used to increase the loading of the drug. The SB415286 nanoformulation efficiently inhibited PD-1 expression in chimeric antigen receptor (CAR)-T cells co-cultured with tumour cells expressing the CAR target, and improved their survival and proliferation. Treatment of the CAR-T cells with nanoformulation also increased the population of memory T-cells. The nanoformulation of small molecule inhibitor of the GSK3 pathway is a promising alternative to antibody-based checkpoint inhibition that warrants further studies.

Keywords:  Glycogen synthase kinase 3; Immune checkpoint; Immunotherapy; Nanoparticle; Oncology

DOI:  https://doi.org/10.1016/j.ijpharm.2022.121845
Neurology. 2022 May 26. pii: 10.1212/WNL.0000000000200746. [Epub ahead of print]

Long-term Safety and Efficacy of Avalglucosidase Alfa in Patients With Late-Onset Pompe Disease.

NEO-EXT investigators

BACKGROUND AND OBJECTIVES: Pompe disease is a rare, progressive neuromuscular disorder caused by deficiency of lysosomal acid α-glucosidase (GAA) and subsequent glycogen accumulation. Avalglucosidase alfa, a recombinant human GAA enzyme replacement therapy designed for increased cellular uptake and glycogen clearance, has been studied for long-term efficacy and safety in patients with late-onset Pompe disease (LOPD). Here we report up to 6.5 years' experience with avalglucosidase alfa during the NEO1 and NEO-EXT studies.
METHODS: NEO1 participants with LOPD, either treatment-naïve (Naïve Group) or receiving alglucosidase alfa for ≥9 months (Switch Group), received avalglucosidase alfa (5, 10, or 20 mg/kg every other week [qow]) for 6 months before entering NEO-EXT and continued their NEO1 dose until all proceeded with 20 mg/kg qow. Safety and efficacy, a pre-specified exploratory secondary outcome, were assessed; slopes of change for efficacy outcomes were calculated from a repeated mixed-measures model.
RESULTS: Twenty-four participants enrolled in NEO1 (Naïve Group, n=10; Switch Group, n=14); 21 completed and 19 entered NEO-EXT; in February 2020, 17 participants remained in NEO-EXT, with data up to 6.5 years. Avalglucosidase alfa was generally well-tolerated during NEO-EXT, with a safety profile consistent with that in NEO1. No deaths or treatment-related life-threatening serious adverse events occurred. Eighteen participants developed anti-drug antibodies without apparent impact on clinical outcomes. No participants who were tested developed immunoglobulin E antibodies. Upright forced vital capacity (FVC) %predicted remained stable in most participants, with slope estimates (95% confidence intervals) of -0.473/year (-1.188, 0.242) and -0.648/year (-1.061, -0.236) in the Naïve and Switch Groups, respectively. Six-minute walk test (6MWT) %predicted was also stable for most participants, with slope estimates of -0.701/year (-1.571, 0.169) and -0.846/year (-1.567, -0.125) for the Naïve and Switch Groups, respectively. Improvements in 6MWT distance were observed in most participants aged <45 years at NEO1 enrollment, in both the Naïve and Switch Groups.
DISCUSSION: Avalglucosidase alfa was generally well-tolerated for up to 6.5 years in adult participants with LOPD either naïve to alglucosidase alfa or who had previously received alglucosidase alfa for ≥9 months.Classification of Evidence: This study provides Class IV evidence of long-term tolerability and sustained efficacy of avalglucosidase alfa in patients with LOPD after up to 6.5 years.

DOI: https://doi.org/10.1212/WNL.0000000000200746
Am J Pathol. 2022 May 20. pii: S0002-9440(22)00146-8. [Epub ahead of print]

BNIP3 is involved in muscle fiber atrophy in Late-Onset Pompe Disease patients.

Ana Carrasco-Rozas, Esther Fernández-Simón, Xavier Suárez-Calvet, Patricia Piñol-Jurado, Jorge Alonso-Pérez, Noemí de Luna, Benedikt Schoser, Peter Meinke, Cristina Domínguez-González, Aurelio Hernández-Laín, Carmen Paradas, Eloy Rivas, Isabel Illa, Montse Olivé, Eduard Gallardo, Jordi Díaz-Manera.

Late-onset Pompe disease (LOPD) is a rare genetic disorder produced by mutations in the GAA gene and is characterized by progressive muscle weakness. LOPD muscle biopsies show accumulation of glycogen along with the autophagic vacuoles associated with atrophic muscle fibers. The expression of molecules related to muscle fiber atrophy in muscle biopsies of LOPD patients was studied using immunofluorescence (IF) and Real-Time PCR. BNIP3, a well-known atrogene, was identified as a potential mediator of muscle fiber atrophy in LOPD muscle biopsies. We observed that vacuolated fibers in LOPD patients muscle biopsies were smaller than non-vacuolated fibers and expressed BNIP3. Our data suggested that BNIP3 expression is regulated by inhibition of the AKT-mTOR pathway, leading to phosphorylation of ULK1 at Ser317 by AMPK. We studied myoblasts and myotubes obtained from LOPD patients and age-matched controls to confirm these results using different molecular techniques. Myotubes derived from LOPD patients were likewise smaller and expressed BNIP3. Conclusively, transfection of BNIP3 into control myotubes leads to myotube atrophy. These findings suggest a cascade which starts with the inhibition of the AKT-mTOR pathway and activation of BNIP3 expression leading to progressive muscle fiber atrophy. Our results open the door to potential new treatments targeting BNIP3 to reduce its deleterious effects on muscle fiber atrophy in Pompe disease.

DOI: https://doi.org/10.1016/j.ajpath.2022.05.003
Biochem Biophys Rep. 2022 Jul;30 101280

Expression of a constitutively active insulin receptor in Drosulfakinin (Dsk) neurons regulates metabolism and sleep in Drosophila.

Justin Palermo, Alex C Keene, Justin R DiAngelo.

  The ability of organisms to sense their nutritional environment and adjust their behavior accordingly is critical for survival. Insulin-like peptides (ilps) play major roles in controlling behavior and metabolism; however, the tissues and cells that insulin acts on to regulate these processes are not fully understood. In the fruit fly, Drosophila melanogaster, insulin signaling has been shown to function in the fat body to regulate lipid storage, but whether ilps act on the fly brain to regulate nutrient storage is not known. In this study, we manipulate insulin signaling in defined populations of neurons in Drosophila and measure glycogen and triglyceride storage. Expressing a constitutively active form of the insulin receptor (dInR) in the insulin-producing cells had no effect on glycogen or triglyceride levels. However, activating insulin signaling in the Drosulfakinin (Dsk)-producing neurons led to triglyceride accumulation and increased food consumption. The expression of ilp2, ilp3 and ilp5 was increased in flies with activated insulin signaling in the Dsk neurons, which along with the feeding phenotype, may cause the triglyceride storage phenotypes observed in these flies. In addition, expressing a constitutively active dInR in Dsk neurons resulted in decreased sleep in the fed state and less starvation-induced sleep suppression suggesting a role for insulin signaling in regulating nutrient-responsive behaviors. Together, these data support a role for insulin signaling in the Dsk-producing neurons for regulating behavior and maintaining metabolic homeostasis.

Keywords:  Drosophila; Dsk; Feeding; Metabolism; Sleep; ilp

DOI:  https://doi.org/10.1016/j.bbrep.2022.101280
Int J Mol Sci. 2022 May 17. pii: 5582. [Epub ahead of print]23(10):

Glucocorticoid Receptor β Overexpression Has Agonist-Independent Insulin-Mimetic Effects on HepG2 Glucose Metabolism.

Claudia Sepúlveda-Quiñenao, Juan M Rodriguez, Francisco Díaz-Castro, Andrea Del Campo, Roberto Bravo-Sagua, Rodrigo Troncoso.

  Glucocorticoids (GC) are steroids hormones that drive circulating glucose availability through gluconeogenesis in the liver. However, alternative splicing of the GR mRNA produces two isoforms, termed GRα and GRβ. GRα is the classic receptor that binds to GCs and mediates the most described actions of GCs. GRβ does not bind GCs and acts as a dominant-negative inhibitor of GRα. Moreover, GRβ has intrinsic and GRα-independent transcriptional activity. To date, it remains unknown if GRβ modulates glucose handling in hepatocytes. Therefore, the study aims to characterize the impact of GRβ overexpression on glucose uptake and storage using an in vitro hepatocyte model. Here we show that GRβ overexpression inhibits the induction of gluconeogenic genes by dexamethasone. Moreover, GRβ activates the Akt pathway, increases glucose transports mRNA, increasing glucose uptake and glycogen storage as an insulin-mimetic. Our results suggest that GRβ has agonist-independent insulin-mimetic actions in HepG2 cells.

Keywords:  glucocorticoid receptor β; glucose; glycogen; insulin; liver

DOI:  https://doi.org/10.3390/ijms23105582
Oncogenesis. 2022 May 23. 11(1): 28

GSK3β palmitoylation mediated by ZDHHC4 promotes tumorigenicity of glioblastoma stem cells in temozolomide-resistant glioblastoma through the EZH2-STAT3 axis.

Chenggang Zhao, Huihan Yu, Xiaoqing Fan, Wanxiang Niu, Junqi Fan, Suling Sun, Meiting Gong, Bing Zhao, Zhiyou Fang, Xueran Chen.

Glioblastoma stem cells (GSCs) are a highly tumorigenic cell subgroup of glioblastoma (GBM). Glycogen synthase kinase 3β (GSK3β) is considered a key hub for promoting malignant phenotypes in GBM. However, the functional relationships between GSK3β and GSCs in GBM are unclear. Here, we found that GSK3β was noted as a substrate for ZDHHC4-mediated palmitoylation at the Cys14 residue, which enhanced GBM temozolomide (TMZ) resistance and GSC self-renewal. Clinically, the expression level of ZDHHC4 was upregulated in GBM, which significantly correlated with tumor grade and poor prognosis. The above phenotypes were based on decreasing p-Ser9 and increasing p-Tyr216 by GSK3β palmitoylation, which further activated the enhancer of the zeste homolog 2 (EZH2)-STAT3 pathway. Notably, STAT3 silencing also inhibited ZDHHC4 expression. This study revealed that GSK3β palmitoylation mediated by ZDHHC4 improved the stemness of TMZ-resistant GBM by activating the EZH2-STAT3 signaling axis, providing a new theoretical basis for further understanding the mechanism of TMZ resistance and recurrence after treatment.

DOI: https://doi.org/10.1038/s41389-022-00402-w
Aging (Albany NY). 2022 May 23. 14(undefined):

Long-term treatment with chloroquine increases lifespan in middle-aged male mice possibly via autophagy modulation, proteasome inhibition and glycogen metabolism.

Thorsten R Doeppner, Cristin Coman, Daiana Burdusel, Diana-Larisa Ancuta, Ulf Brockmeier, Daniel Nicolae Pirici, Kuang Yaoyun, Dirk M Hermann, Aurel Popa-Wagner.

  Previous studies have shown that the polyamine spermidine increased the maximum life span in C. elegans and the median life span in mice. Since spermidine increases autophagy, we asked if treatment with chloroquine, an inhibitor of autophagy, would shorten the lifespan of mice. Recently, chloroquine has intensively been discussed as a treatment option for COVID-19 patients. To rule out unfavorable long-term effects on longevity, we examined the effect of chronic treatment with chloroquine given in the drinking water on the lifespan and organ pathology of male middle-aged NMRI mice. We report that, surprisingly, daily treatment with chloroquine extended the median life span by 11.4% and the maximum life span of the middle-aged male NMRI mice by 11.8%. Subsequent experiments show that the chloroquine-induced lifespan elevation is associated with dose-dependent increase in LC3B-II, a marker of autophagosomes, in the liver and heart that was confirmed by transmission electron microscopy. Quite intriguingly, chloroquine treatment was also associated with a decrease in glycogenolysis in the liver suggesting a compensatory mechanism to provide energy to the cell. Accumulation of autophagosomes was paralleled by an inhibition of proteasome-dependent proteolysis in the liver and the heart as well as with decreased serum levels of insulin growth factor binding protein-3 (IGFBP3), a protein associated with longevity. We propose that inhibition of proteasome activity in conjunction with an increased number of autophagosomes and decreased levels of IGFBP3 might play a central role in lifespan extension by chloroquine in male NMRI mice.

Keywords:  autophagy; chloroquine; longevity; middle-aged mice; proteasome; toxicity

DOI:  https://doi.org/10.18632/aging.204069