scholarly journals Misrouting of glucagon and stathmin-2 towards lysosomal system of α-cells in glucagon hypersecretion of diabetes

Islets ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 40-57
Author(s):  
Farzad Asadi ◽  
Savita Dhanvantari
Keyword(s):  
Lysosomal System

Immunocytochemical Localization of Amyloid Protein AA in the “Dense Fibrillar Inclusions” of the Reticuloendothelical Cells

1977 ◽  
Vol 35 ◽  
pp. 438-439
Author(s):  
T. Shirahama ◽  
M. Skinner ◽  
A.S. Cohen
Keyword(s):  
Amyloid Fibril ◽  
Close Association ◽  
Gel Filtration ◽  
Fibril Formation ◽  
Amyloid Protein ◽  
Electron Microscopic ◽  
Amyloid Deposits ◽  
Amyloid Fibril Formation ◽  
Electron Microscopic Technique ◽  
Lysosomal System

A1thought the mechanisms of amyloidogenesis have not been entirely clarified, proteolysis of the parent proteins may be one of the important steps in the amyloid fibril formation. Recently, we reported that "dense fibrillar inclusions" (DFI), which had the characteristics of lysosomes and contained organized fibrillar profiles as well, were observed in the reticuloendothelial cells in close association with the foci of new amyloid deposits. We considered the findings as evidence for the involvement of lysosomal system in amyloid fibril formation (l). In the present study, we attempted to determine the identity of the contents of the DFI by the use of antisera against the amyloid protein (AA) and an immuno-electron microscopic technique.Amyloidosis was induced in CBA/J mice by daily injections of casein (l). AA was isolated from amyloid-laden spleens by gel filtration and antibody to it was produced in rabbits (2). For immunocytochemistry, the unlabeled antibody enzyme method (3) was employed.

scholarly journals Distinct uptake, amplification, and release of SARS-CoV-2 by M1 and M2 alveolar macrophages

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jiadi Lv ◽  
Zhenfeng Wang ◽  
Yajin Qu ◽  
Hua Zhu ◽  
Qiangqiang Zhu ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Mouse Model ◽  
Alveolar Macrophages ◽  
Transgenic Mouse Model ◽  
Lysosomal Ph ◽  
Viral Spread ◽  
Lysosomal System ◽  
Endosomal Ph ◽  
Alternatively Activated ◽  
Classically Activated

AbstractSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) invades the alveoli, where abundant alveolar macrophages (AMs) reside. How AMs respond to SARS-CoV-2 invasion remains elusive. Here, we show that classically activated M1 AMs facilitate viral spread; however, alternatively activated M2 AMs limit the spread. M1 AMs utilize cellular softness to efficiently take up SARS-CoV-2. Subsequently, the invaded viruses take over the endo-lysosomal system to escape. M1 AMs have a lower endosomal pH, favoring membrane fusion and allowing the entry of viral RNA from the endosomes into the cytoplasm, where the virus achieves replication and is packaged to be released. In contrast, M2 AMs have a higher endosomal pH but a lower lysosomal pH, thus delivering the virus to lysosomes for degradation. In hACE2 transgenic mouse model, M1 AMs are found to facilitate SARS-CoV-2 infection of the lungs. These findings provide insights into the complex roles of AMs during SARS-CoV-2 infection, along with potential therapeutic targets.

scholarly journals Melatonin administration provokes the activity of dendritic reticular cells in the seminal vesicle of Soay ram during the non-breeding season

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hanan H. Abd-Elhafeez ◽  
A. H. S. Hassan ◽  
Manal T. Hussein
Keyword(s):  
Estrogen Receptor Alpha ◽  
Close Contact ◽  
Secretory Activity ◽  
Treated Group ◽  
Nerve Fibers ◽  
Stimulatory Action ◽  
Transmission Electron ◽  
Melatonin Administration ◽  
S 100 ◽  
Lysosomal System

AbstractDendritic cells (DCs) are innate immune cells which engulf, process and present antigens to the naïve T-lymphocyte cells. However, little is known about the effect of melatonin on the DCs. The present study aimed to investigate the morphology and distribution of the DCs by transmission electron microscopy and Immunohistochemistry after melatonin administration. A total of 8 out of 15 adult ram was randomly selected to receive the melatonin implant and the remaining 7 animals received melatonin free implants. DCs showed positive immunoreactivity for CD117, S-100 protein and CD34. There is an obvious increase in the number of the positive immunoreactive cells to CD3, estrogen receptor alpha and progesterone in the treated groups. The expression of CD56 and MHCII in the DCs was abundant in the treated groups. The ultrastructure study revealed that melatonin exerts a stimulatory effect on the DCs which was associated with increment in the secretory activity of DCs. The secretory activity demarcated by an obvious increase in the number of mitochondria, cisternae of rER and a well-developed Golgi apparatus. The endosomal- lysosomal system was more developed in the treated groups. A rod-shaped Birbeck granule was demonstrated in the cytoplasm of the melatonin treated group. DCs were observed in a close contact to telocytes, T-Lymphocytes, nerve fibers and blood vessels. Taken together, melatonin administration elicits a stimulatory action on the DCs and macrophages through increasing the size, the number and the endosomal compartments which may correlate to increased immunity.

scholarly journals Sequestration of cytoplasmic enzymes in an autophagic vacuole-lysosomal system induced by injection of leupeptin.

1983 ◽  
Vol 258 (10) ◽  
pp. 6093-6100 ◽  
Author(s):  
E Kominami ◽  
S Hashida ◽  
E A Khairallah ◽  
N Katunuma
Keyword(s):  
Autophagic Vacuole ◽  
Lysosomal System

The microglial lysosomal system in Alzheimer’s disease: guardian against proteinopathy

2021 ◽  
pp. 101444
Author(s):  
Zoë P. Van Acker ◽  
Anika Perdok ◽  
Marine Bretou ◽  
Wim Annaert
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Lysosomal System

scholarly journals EFFECTS OF GLUCONEOGENIC AGENTS ON THE LYSOSOMAL SYSTEM

1978 ◽  
Vol 11 (3) ◽  
pp. 232-238 ◽  
Author(s):  
SHOGO ABE ◽  
KAZUO OGAWA
Keyword(s):  
Lysosomal System

Intracellular digestion and cellular defecation in a monogenean, Diclidophora merlangi

Parasitology ◽  
1975 ◽  
Vol 70 (3) ◽  
pp. 331-340 ◽  
Author(s):  
D. W. Halton
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Digestive Enzymes ◽  
Host Protein ◽  
Blood Proteins ◽  
Host Fish ◽  
Intracellular Digestion ◽  
Thiamine Pyrophosphatase ◽  
Lysosomal System ◽  
Pyrophosphatase Activity

The ultrastructural and cytochemical changes accompanying intracellular digestion and cellular defecation in the haematin cell of Diclidophora merlangi have been described. Blood proteins of the host-fish are sequestered by endocytosis and degraded within an interconnecting network of channels that form an integral, but changing, part of the cell. The digestive enzymes involved originate in the granular endoplasmic reticulum and are packaged in the Golgi apparatus and transferred to the channels in Golgi vesicles. The rate of haemoglobin absorption and the activity of the Golgi, as judged by vesicle counts and staining intensities for thiamine pyrophosphatase activity, are stimulated by the introduction of host protein into the gut lumen. The haematin residues of digestion are extruded periodically into the lumen by exocytosis involving membrane fusion. The process is a continuous one and, in worms starved of food, can result in the complete evacuation of pigment from the cell. It is suggested that a lysosomal system operates in the digestive cycle of the haematin cell.

scholarly journals Intracellular distribution of amyloid beta peptide and its relationship to the lysosomal system

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Lin Zheng ◽  
Angel Cedazo-Minguez ◽  
Martin Hallbeck ◽  
Fredrik Jerhammar ◽  
Jan Marcusson ◽  
...  
Keyword(s):  
Amyloid Beta ◽  
Intracellular Distribution ◽  
Amyloid Beta Peptide ◽  
Beta Peptide ◽  
Lysosomal System

scholarly journals Endo-lysosomal Aβ concentration and pH enable formation of Aβ oligomers that potently induce Tau missorting

2020 ◽  
Author(s):  
Marie P. Schützmann ◽  
Filip Hasecke ◽  
Sarah Bachmann ◽  
Mara Zielinski ◽  
Sebastian Hänsch ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Tau Pathology ◽  
Aβ Oligomers ◽  
Lysosomal Ph ◽  
Amyloid Fibril Formation ◽  
Aβ Amyloid ◽  
Key Factor ◽  
Lysosomal System

AbstractAmyloid-β peptide (Aβ) forms metastable oligomers >50 kD, termed AβOs or protofibrils, that are more effective than Aβ amyloid fibrils at triggering Alzheimer’s disease-related processes such as synaptic dysfunction and Tau pathology, including Tau mislocalization. In neurons, Aβ accumulates in endo-lysosomal vesicles at low pH. Here, we show that the rate of AβO assembly is accelerated 8,000-fold upon pH reduction from extracellular to endo-lysosomal pH, at the expense of amyloid fibril formation. The pH-induced promotion of AβO formation and the high endo-lysosomal Aβ concentration together enable extensive AβO formation of Aβ42 under physiological conditions. Exploiting the enhanced AβO formation of the dimeric Aβ variant dimAβ we furthermore demonstrate targeting of AβOs to dendritic spines, potent induction of Tau missorting, a key factor in tauopathies, and impaired neuronal activity. The results suggest that the endosomal/lysosomal system is a major site for the assembly of pathomechanistically relevant AβOs.

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