Ultrastructural Localization of Histidine-rich Glycoprotein in Skeletal Muscle Fibers: Colocalization With AMP Deaminase

Mattii, Letizia; Bianchi, Francesco; Falleni, Alessandra; Frascarelli, Sabina; Masini, Matilde; Alì, Greta; Chiellini, Grazia; Sabbatini, Antonietta Raffaella Maria

doi:10.1369/0022155419897573

Cited by 5 publications

(3 citation statements)

References 34 publications

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“…Tissue blocks were dehydrated in a serial gradient of ethanol solutions (30%, 50%, 70%, 90% and 95% for 5 min, and 100% for 60 min) to be embedded in epoxy resin. The concentration of the fixing and post-fixing solutions along with the use of the epoxy embedding resin were validated in previous studies using immuno-gold at ultrastructural morphometry [ 32 , 33 ]. In fact, the combination of aldehydes, OsO 4 , and epoxy resin allows a minimal epitope covering while preserving sub-cellular architecture [ 34 , 35 , 36 ].…”

Section: Methodsmentioning

confidence: 99%

Within the Ischemic Penumbra, Sub-Cellular Compartmentalization of Heat Shock Protein 70 Overlaps with Autophagy Proteins and Fails to Merge with Lysosomes

et al. 2022

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The brain area which surrounds the frankly ischemic region is named the area penumbra. In this area, most cells are spared although their oxidative metabolism is impaired. area penumbra is routinely detected by immunostaining of a molecule named Heat Shock Protein 70 (HSP70). Within the area penumbra, autophagy-related proteins also increase. Therefore, in the present study, the autophagy-related microtubule-associated protein I/II-Light Chain 3 (LC3) was investigated within the area penumbra along with HSP70. In C57 black mice, ischemia was induced by permanent occlusion of the distal part of the middle cerebral artery. Immunofluorescence and electron microscopy show that LC3 and HSP70 are overexpressed and co-localize within the area penumbra in the same cells and within similar subcellular compartments. In the area penumbra, marked loss of co-localization of HSP70 and LC3-positive autophagy vacuoles, with lysosomal-associated membrane protein 1 (LAMP1) or cathepsin-D-positive lysosome vacuoles occurs. This study indicates that, within the area penumbra, a failure of autophagolysosomes depends on defective compartmentalization of LC3, LAMP1 and cathepsin-D and a defect in merging between autophagosomes and lysosomes. Such a deleterious effect is likely to induce a depletion of autophagolysosomes and cell clearing systems, which needs to be rescued in the process of improving neuronal survival.

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Section: Methodsmentioning

confidence: 99%

Within the Ischemic Penumbra, Sub-Cellular Compartmentalization of Heat Shock Protein 70 Overlaps with Autophagy Proteins and Fails to Merge with Lysosomes

et al. 2022

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“…Then, the blocks were dehydrated in a serial gradient of ethanol solutions (30%, 50%, 70%, 90% and 95% for 5 min; and 100% for 60 min), and finally, they were embedded in epoxy resin. The concentration of the fixing and post-fixing solutions, along with the use of the epoxy embedding resin, were validated in previous studies performing immuno-gold-based ultrastructural morphometry [ 30 , 31 ]. In fact, the combination of aldehydes, OsO 4 , and epoxy resin allows a minimal epitope covering while preserving sub-cellular architecture [ 13 , 32 , 33 ].…”

Section: Methodsmentioning

confidence: 99%

The Autophagy-Related Organelle Autophagoproteasome Is Suppressed within Ischemic Penumbra

Biagioni

Mastroiacovo

Lenzi

et al. 2021

IJMS

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The peri-infarct region, which surrounds the irreversible ischemic stroke area is named ischemic penumbra. This term emphasizes the borderline conditions for neurons placed within such a critical region. Area penumbra separates the ischemic core, where frank cell loss occurs, from the surrounding healthy brain tissue. Within such a brain region, nervous matter, and mostly neurons are impaired concerning metabolic conditions. The classic biochemical marker, which reliably marks area penumbra is the over-expression of the heat shock protein 70 (HSP70). However, other proteins related to cell clearing pathways are modified within area penumbra. Among these, autophagy proteins like LC3 increase in a way, which recapitulates Hsp70. In contrast, components, such as P20S, markedly decrease. Despite apparent discrepancies, the present study indicates remarkable overlapping between LC3 and P20S redistribution within area penumbra. In fact, the amount of both proteins is markedly reduced within vacuoles. Specifically, a massive loss of LC3 + P20S immuno-positive vacuoles (autophagoproteasomes) is reported here. This represents the most relevant sub-cellular alteration here described in cell clearing pathways within area penumbra. The functional significance of these findings remains to be determined and it will take a novel experimental stream to decipher the fine-tuning of such a phenomenon.

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“…More recently, transmission electron microscopy and immunogold analysis evidenced the presence of HPRG in the sarcomeres, mainly in the I-band. Using the double immunogold staining, a colabeling of HPRG and AMPD1 was evident at sarcomeric, sarcoplasmic reticulum and nuclear levels [ 130 ].…”

Section: Introductionmentioning

confidence: 99%

Role of the interaction between troponin T and AMP deaminase by zinc bridge in modulating muscle contraction and ammonia production

Ronca

Raggi

2023

Mol Cell Biochem

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The N-terminal region of troponin T (TnT) does not bind any protein of the contractile machinery and the role of its hypervariability remains uncertain. In this review we report the evidence of the interaction between TnT and AMP deaminase (AMPD), a regulated zinc enzyme localized on the myofibril. In periods of intense muscular activity, a decrease in the ATP/ADP ratio, together with a decrease in the tissue pH, is the stimulus for the activation of the enzyme that deaminating AMP to IMP and NH3 displaces the myokinase reaction towards the formation of ATP. In skeletal muscle subjected to strong tetanic contractions, a calpain-like proteolytic activity produces the removal in vivo of a 97-residue N-terminal fragment from the enzyme that becomes desensitized towards the inhibition by ATP, leading to an unrestrained production of NH3. When a 95-residue N-terminal fragment is removed from AMPD by trypsin, simulating in vitro the calpain action, rabbit fast TnT or its phosphorylated 50-residue N-terminal peptide binds AMPD restoring the inhibition by ATP. Taking in consideration that the N-terminus of TnT expressed in human as well as rabbit white muscle contains a zinc-binding motif, we suggest that TnT might mimic the regulatory action of the inhibitory N-terminal domain of AMPD due to the presence of a zinc ion connecting the N-terminal and C-terminal regions of the enzyme, indicating that the two proteins might physiologically associate to modulate muscle contraction and ammonia production in fast-twitching muscle under strenuous conditions.

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Ultrastructural Localization of Histidine-rich Glycoprotein in Skeletal Muscle Fibers: Colocalization With AMP Deaminase

Cited by 5 publications

References 34 publications

Within the Ischemic Penumbra, Sub-Cellular Compartmentalization of Heat Shock Protein 70 Overlaps with Autophagy Proteins and Fails to Merge with Lysosomes

Within the Ischemic Penumbra, Sub-Cellular Compartmentalization of Heat Shock Protein 70 Overlaps with Autophagy Proteins and Fails to Merge with Lysosomes

The Autophagy-Related Organelle Autophagoproteasome Is Suppressed within Ischemic Penumbra

Role of the interaction between troponin T and AMP deaminase by zinc bridge in modulating muscle contraction and ammonia production

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