bims-lypmec 2024-07-07 papers

bims-lypmec

Biomed News

on Lysosomal positioning and metabolism in cardiomyocytes

Issue of 2024‒07‒07
seven papers selected by
Satoru Kobayashi, New York Institute of Technology

Two-Step Enrichment Facilitates Background Reduction for Proteomic Analysis of Lysosomes.
ER-to-lysosome Ca2+ refilling followed by K+ efflux-coupled store-operated Ca2+ entry in inflammasome activation and metabolic inflammation.
Metabolic stress induces a double-positive feedback loop between AMPK and SQSTM1/p62 conferring dual activation of AMPK and NFE2L2/NRF2 to synergize antioxidant defense.
Systemic Deletion of ARRDC4 Improves Cardiac Reserve and Exercise Capacity in Diabetes.
Mitochondrial Structure and Function in Human Heart Failure.
A Dual-Labeling Molecule for Efficient Drug Discovery of Mitochondrial-Lysosomal Interactions.
Roles of non-coding RNA in diabetic cardiomyopathy.

J Proteome Res. 2024 Jul 05.

Two-Step Enrichment Facilitates Background Reduction for Proteomic Analysis of Lysosomes.

Sara Bonini, Dominic Winter.

  Lysosomes constitute the main degradative compartment of most mammalian cells and are involved in various cellular functions. Most of them are catalyzed by lysosomal proteins, which typically are low abundant, complicating their analysis by mass spectrometry-based proteomics. To increase analytical performance and to enable profiling of lysosomal content, lysosomes are often enriched. Two approaches have gained popularity in recent years, namely, superparamagnetic iron oxide nanoparticles (SPIONs) and immunoprecipitation from cells overexpressing a 3xHA-tagged version of TMEM192 (TMEM-IP). The effect of these approaches on the lysosomal proteome has not been investigated to date. We addressed this topic through a combination of both techniques and proteomic analysis of lysosome-enriched fractions. For SPIONs treatment, we identified altered cellular iron homeostasis and moderate changes of the lysosomal proteome. For overexpression of TMEM192, we observed more pronounced effects in lysosomal protein expression, especially for lysosomal membrane proteins and those involved in protein trafficking. Furthermore, we established a combined strategy based on the sequential enrichment of lysosomes with SPIONs and TMEM-IP. This enabled increased purity of lysosome-enriched fractions and, through TMEM-IP-based lysosome enrichment from SPIONs flow-through and eluate fractions, additional insights into the properties of individual approaches. All data are available via ProteomeXchange with PXD048696.

Keywords:  HEK 293; TMEM192; lysosome enrichment; lysosomes; mass spectrometry; organelles; proteomics; superparamagnetic iron oxide nanoparticles (SPIONs)

DOI:  https://doi.org/10.1021/acs.jproteome.4c00053
Elife. 2024 Jul 02. pii: RP87561. [Epub ahead of print]12

ER-to-lysosome Ca2+ refilling followed by K+ efflux-coupled store-operated Ca2+ entry in inflammasome activation and metabolic inflammation.

Hyereen Kang, Seong Woo Choi, Joo Young Kim, Soo-Jin Oh, Sung Joon Kim, Myung-Shik Lee.

  We studied lysosomal Ca2+ in inflammasome. Lipopolysaccharide (LPS) + palmitic acid (PA) decreased lysosomal Ca2+ ([Ca2+]Lys) and increased [Ca2+]i through mitochondrial ROS, which was suppressed in Trpm2-KO macrophages. Inflammasome activation and metabolic inflammation in adipose tissue of high-fat diet (HFD)-fed mice were ameliorated by Trpm2 KO. ER→lysosome Ca2+ refilling occurred after lysosomal Ca2+ release whose blockade attenuated LPS + PA-induced inflammasome. Subsequently, store-operated Ca2+entry (SOCE) was activated whose inhibition suppressed inflammasome. SOCE was coupled with K+ efflux whose inhibition reduced ER Ca2+ content ([Ca2+]ER) and impaired [Ca2+]Lys recovery. LPS + PA activated KCa3.1 channel, a Ca2+-activated K+ channel. Inhibitors of KCa3.1 channel or Kcnn4 KO reduced [Ca2+]ER, attenuated increase of [Ca2+]i or inflammasome activation by LPS + PA, and ameliorated HFD-induced inflammasome or metabolic inflammation. Lysosomal Ca2+ release induced delayed JNK and ASC phosphorylation through CAMKII-ASK1. These results suggest a novel role of lysosomal Ca2+ release sustained by ER→lysosome Ca2+ refilling and K+ efflux through KCa3.1 channel in inflammasome activation and metabolic inflammation.

Keywords:  diabetes; immunology; inflammation; lipid; lysosome; mouse

DOI:  https://doi.org/10.7554/eLife.87561
Autophagy. 2024 Jul 02.

Metabolic stress induces a double-positive feedback loop between AMPK and SQSTM1/p62 conferring dual activation of AMPK and NFE2L2/NRF2 to synergize antioxidant defense.

Eun-Ji Choi, Hyun-Taek Oh, Seon-Hyeong Lee, Chen-Song Zhang, Mengqi Li, Soo-Youl Kim, Sunghyouk Park, Tong-Shin Chang, Byung-Hoon Lee, Sheng-Cai Lin, Sang-Min Jeon.

  Co-occurring mutations in KEAP1 in STK11/LKB1-mutant NSCLC activate NFE2L2/NRF2 to compensate for the loss of STK11-AMPK activity during metabolic adaptation. Characterizing the regulatory crosstalk between the STK11-AMPK and KEAP1-NFE2L2 pathways during metabolic stress is crucial for understanding the implications of co-occurring mutations. Here, we found that metabolic stress increased the expression and phosphorylation of SQSTM1/p62, which is essential for the activation of NFE2L2 and AMPK, synergizing antioxidant defense and tumor growth. The SQSTM1-driven dual activation of NFE2L2 and AMPK was achieved by inducing macroautophagic/autophagic degradation of KEAP1 and facilitating the AXIN-STK11-AMPK complex formation on the lysosomal membrane, respectively. In contrast, the STK11-AMPK activity was also required for metabolic stress-induced expression and phosphorylation of SQSTM1, suggesting a double-positive feedback loop between AMPK and SQSTM1. Mechanistically, SQSTM1 expression was increased by the PPP2/PP2A-dependent dephosphorylation of TFEB and TFE3, which was induced by the lysosomal deacidification caused by low glucose metabolism and AMPK-dependent proton reduction. Furthermore, SQSTM1 phosphorylation was increased by MAP3K7/TAK1, which was activated by ROS and pH-dependent secretion of lysosomal Ca2+. Importantly, phosphorylation of SQSTM1 at S24 and S226 was critical for the activation of AMPK and NFE2L2. Notably, the effects caused by metabolic stress were abrogated by the protons provided by lactic acid. Collectively, our data reveal a novel double-positive feedback loop between AMPK and SQSTM1 leading to the dual activation of AMPK and NFE2L2, potentially explaining why co-occurring mutations in STK11 and KEAP1 happen and providing promising therapeutic strategies for lung cancer.

Keywords:  AXIN; KEAP1; STK11/LKB1; lysosomal stress; metabolic stress; oxidative stress

DOI:  https://doi.org/10.1080/15548627.2024.2374692
Circ Res. 2024 Jul 01.

Systemic Deletion of ARRDC4 Improves Cardiac Reserve and Exercise Capacity in Diabetes.

Yoshinobu Nakayama, Satoru Kobayashi, Aliya Masihuddin, Syed Amir Abdali, A M Pramodh Bandara Seneviratne, Sachiyo Ishii, Jun Iida, Qiangrong Liang, Jun Yoshioka.

  BACKGROUND: Exercise intolerance is an independent predictor of poor prognosis in diabetes. The underlying mechanism of the association between hyperglycemia and exercise intolerance remains undefined. We recently demonstrated that the interaction between ARRDC4 (arrestin domain-containing protein 4) and GLUT1 (glucose transporter 1) regulates cardiac metabolism.OBJECTIVE: To determine whether this mechanism broadly impacts diabetic complications, we investigated the role of ARRDC4 in the pathogenesis of diabetic cardiac and skeletal myopathy.
METHODS AND RESULTS: High glucose promoted translocation of MondoA into the nucleus, which upregulated Arrdc4 transcriptional expression, increased lysosomal GLUT1 trafficking, and blocked glucose transport in cardiomyocytes, forming a feedback mechanism. This role of ARRDC4 was confirmed in human muscular cells from type 2 diabetic patients. Prolonged hyperglycemia upregulated myocardial Arrdc4 expression in multiple types of mouse models of diabetes. We then analyzed hyperglycemia-induced cardiac and skeletal muscle abnormalities in insulin-deficient mice. Hyperglycemia increased advanced glycation end-products and elicited oxidative and endoplasmic reticulum stress leading to apoptosis in the heart and peripheral muscle. However, deletion of Arrdc4 augmented tissue glucose transport and mitochondrial respiration, protecting the heart and muscle from tissue damage. Stress hemodynamic analysis and treadmill exhaustion test uncovered that Arrdc4-knockout mice had greater cardiac inotropic/chronotropic reserve with higher exercise endurance than wild-type (WT) animals under diabetes. While multiple organs were involved in the mechanism, cardiac-specific overexpression (beyond levels observed during diabetes) using adenoassociated virus suggests that high levels of myocardial ARRDC4 have the potential to contribute to exercise intolerance by interfering with cardiac metabolism through its interaction with GLUT1 in diabetes. Importantly, the ARRDC4 mutation mouse line exhibited greater exercise tolerance, showing the potential therapeutic impact on diabetic cardiomyopathy by disrupting the interaction between ARRDC4 and GLUT1.
CONCLUSIONS: ARRDC4 serves as a regulator of hyperglycemia-induced toxicities toward cardiac and skeletal muscle, revealing a new molecular framework that connects hyperglycemia to cardiac/skeletal myopathy to exercise intolerance.

Keywords:  adaptor protein; diabetic cardiomyopathy; energy metabolism; exercise endurance; health

DOI:  https://doi.org/10.1161/CIRCRESAHA.123.323158
Circ Res. 2024 Jul 05. 135(2): 372-396

Mitochondrial Structure and Function in Human Heart Failure.

Antentor Hinton, Steven M Claypool, Kit Neikirk, Nanami Senoo, Celestine N Wanjalla, Annet Kirabo, Clintoria R Williams.

  Despite clinical and scientific advancements, heart failure is the major cause of morbidity and mortality worldwide. Both mitochondrial dysfunction and inflammation contribute to the development and progression of heart failure. Although inflammation is crucial to reparative healing following acute cardiomyocyte injury, chronic inflammation damages the heart, impairs function, and decreases cardiac output. Mitochondria, which comprise one third of cardiomyocyte volume, may prove a potential therapeutic target for heart failure. Known primarily for energy production, mitochondria are also involved in other processes including calcium homeostasis and the regulation of cellular apoptosis. Mitochondrial function is closely related to morphology, which alters through mitochondrial dynamics, thus ensuring that the energy needs of the cell are met. However, in heart failure, changes in substrate use lead to mitochondrial dysfunction and impaired myocyte function. This review discusses mitochondrial and cristae dynamics, including the role of the mitochondria contact site and cristae organizing system complex in mitochondrial ultrastructure changes. Additionally, this review covers the role of mitochondria-endoplasmic reticulum contact sites, mitochondrial communication via nanotunnels, and altered metabolite production during heart failure. We highlight these often-neglected factors and promising clinical mitochondrial targets for heart failure.

Keywords:  cardiovascular diseases; heart failure; hypertension; mitochondria; myocardium

DOI:  https://doi.org/10.1161/CIRCRESAHA.124.323800
Mol Cell Probes. 2024 Jul 01. pii: S0890-8508(24)00020-3. [Epub ahead of print] 101968

A Dual-Labeling Molecule for Efficient Drug Discovery of Mitochondrial-Lysosomal Interactions.

Jinfang Wu, Xiaolei Wang, Xiang Li, Zixuan Zhu, Zhongcheng Cui, Tao Zhang, Weiwei Zou, Guanying Han.

  The close association between organelle interactions, such as mitochondrial-lysosomal interactions, and various diseases, including tumors, remains a challenge for drug discovering and identification. Conventional evaluation methods are often complex and multistep labeling procedures often generate false positives, such as cell damage. To overcome these limitations, we employed a single dual-color reporting molecule called Coupa, which labels mitochondria and lysosomes as blue and red, respectively. This facilitates the evaluation and discovering of drugs targeting mitochondria-lysosome contact (MLC). Using Coupa, we validated the effectiveness of various known antitumor drugs in intervening MLC by assessing their effect on key aspects, such as status, localization, and quantity. This provides evidence for the accuracy and applicability of our dual-color reporting molecule. Notably, we observed that several structural isomers of drugs, including Urolithin (A/B/C), exhibited distinct effects on MLC. In addition, Verteporfin and TEAD were found to induce anti-tumor effects by controlling MLC at the organelle level, suggesting a potential new mechanism of action. Collectively, Coupa offers a novel scientific tool for discovering drugs that target mitochondrial-lysosomal interactions. It not only distinguished the differential effects of structurally similar drugs on the same target, but also reveals new mechanisms underlying the reported antitumor properties of existing drugs. Ultimately, our findings contribute to the advancement of drug discovery and provide valuable insights into the complex interactions between organelles in a disease context.

Keywords:  drug discovering; lysosome; mitochondria; mitochondrial-lysosomal interaction; sensor

DOI:  https://doi.org/10.1016/j.mcp.2024.101968
Cardiovasc Diabetol. 2024 Jun 29. 23(1): 227

Roles of non-coding RNA in diabetic cardiomyopathy.

Xi Yao, Xinyue Huang, Jianghua Chen, Weiqiang Lin, Jingyan Tian.

  In recent years, the incidence of diabetes has been increasing rapidly, posing a serious threat to human health. Diabetic cardiomyopathy (DCM) is characterized by cardiomyocyte hypertrophy, myocardial fibrosis, apoptosis, ventricular remodeling, and cardiac dysfunction in individuals with diabetes, ultimately leading to heart failure and mortality. However, the underlying mechanisms contributing to DCM remain incompletely understood. With advancements in molecular biology technology, accumulating evidence has shown that numerous non-coding RNAs (ncRNAs) crucial roles in the development and progression of DCM. This review aims to summarize recent studies on the involvement of three types of ncRNAs (micro RNA, long ncRNA and circular RNA) in the pathophysiology of DCM, with the goal of providing innovative strategies for the prevention and treatment of DCM.

Keywords:  Diabetic cardiomyopathy; Non-coding RNA; Pathogenesis

DOI:  https://doi.org/10.1186/s12933-024-02252-9