Degradation of GM1 and GM2 by mammalian sialidases

2001 ◽  
Vol 360 (1) ◽  
pp. 233-237 ◽  
Author(s):  
Su-Chen LI ◽  
Yu-Teh LI ◽  
Setsuko MORIYA ◽  
Taeko MIYAGI
Keyword(s):  
Clinical Symptoms ◽  
Activator Protein ◽  
Tay Sachs Disease ◽  
In Vitro Hydrolysis ◽  
Mammalian Tissues ◽  
Gm2 Activator ◽  
Gm2 Activator Protein ◽  
Cytosolic Sialidase

In mammalian tissues, the pathway known for the catabolism ofGM1[Galβ3GalNAcβ4(Neu5Acα3)Galβ4GlcCer;where Cer is ceramide] is the conversion of this ganglioside into GM2 [GalNAcβ4(Neu5Acα3)Galβ4GlcβCer] by β-galactosidase followed by the conversion of GM2 into GM3 (Neu5Acα3Galβ4GlcβCer) by β-N-acetylhexosaminidase A (Hex A). However, the question of whether or not GM1 and GM2 can also be respectively converted into asialo-GM1 (Galβ3GalNAcβ4Galβ4GlcCer; GA1) and asialo-GM2 (GalNAcβ4Galβ4GlcβCer, GA2) by mammalian sialidases has not been resolved. This is due to the fact that sialidases purified from mammalian tissues always contained detergents that interfered with the in vitro hydrolysis of GM1 and GM2 in the presence of an activator protein. The mouse model of human type B Tay–Sachs disease created by the disruption of the Hexa gene showed no neurological abnormalities, with milder clinical symptoms than the human counterpart, and the accumulation of GM2 in the brains of affected mice was only limited to certain regions [Sango, Yamanaka, Hoffmann, Okuda, Grinberg, Westphal, McDonald, Crawley, Sandhoff, Suzuki and Proia (1995) Nat. Genet. 11, 170–176]. These results suggest the possible presence of an alternative catabolic pathway (the GA2 pathway) in mouse to convert GM2 into GA2 by sialidase. To show the existence of this pathway, we have used recombinant mammalian cytosolic sialidase and membrane-associated sialidase to study the desialylation of GM1 and GM2. We found that the mouse membrane-bound sialidase was able to convert GM1 and GM2 into their respective asialo-derivatives in the presence of human or mouse GM2 activator protein. The cytosolic sialidase did not exhibit this activity. Our results suggest that, in vivo, the stable NeuAc of GM1 and GM2 may be removed by the mammalian membrane-associated sialidase in the presence of GM2 activator protein. They also support the presence of the GA2 pathway for the catabolism of GM2 in mouse.

scholarly journals In Cellulo Examination of a Beta-Alpha Hybrid Construct of Beta-Hexosaminidase A Subunits, Reported to Interact with the GM2 Activator Protein and Hydrolyze GM2 Ganglioside

2021 ◽  
Author(s):  
Warren W. Wakarchuk ◽  
Incilay Sinici ◽  
Sayuri Yonekawa ◽  
Ilona Tkachyova ◽  
Steven J. Gray ◽  
...  
Keyword(s):  
In Vitro Assays ◽  
Variant Form ◽  
Gm2 Ganglioside ◽  
Activator Protein ◽  
Hexosaminidase A ◽  
Hybrid Construct ◽  
Gm2 Activator ◽  
Gm2 Activator Protein

The hydrolysis in lysosomes of GM2 ganglioside to GM3 ganglioside requires the correct synthesis, intracellular assembly and transport of three separate gene products; i.e., the alpha and beta subunits of heterodimeric beta-hexosaminidase A, E.C. # 3.2.1.52 (encoded by the HEXA and HEXB genes, respectively), and the GM2-activator protein (GM2AP, encoded by the GM2A gene). Mutations in any one of these genes can result in one of three neurodegenerative diseases collectively known as GM2 gangliosidosis (HEXA, Tay-Sachs disease, MIM # 272800; HEXB, Sandhoff disease, MIM # 268800; and GM2A, AB-variant form, MIM # 272750). Elements of both of the hexosaminidase A subunits are needed to productively interact with the GM2 ganglioside-GM2AP complex in the lysosome. Some of these elements have been predicted from the crystal structures of hexosaminidase and the activator. Recently a hybrid of the two subunits has been constructed and reported to be capable of forming homodimers that can perform this reaction in vivo, which could greatly simplify vector-mediated gene transfer approaches for Tay-Sachs or Sandhoff diseases. A cDNA encoding a hybrid hexosaminidase subunit capable of dimerizing and hydrolyzing GM2 ganglioside could be incorporated into a single vector, whereas packaging both subunits of hexosaminidase A into vectors, such as adeno-associated virus, would be impractical due to size constraints. In this report we examine the previously published hybrid construct (H1) and a new more extensive hybrid (H2), with our documented in cellulo (live cell- based) assay utilizing a fluorescent GM2 ganglioside derivative. Unfortunately when Tay-Sachs cells were transfected with either the H1 or H2 hybrid construct and then were fed the GM2 derivative, no significant increase in its turnover was detected. In vitro assays with the isolated H1 or H2 homodimers confirmed that neither was capable of human GM2AP-dependent hydrolysis of GM2 ganglioside.

scholarly journals In Cellulo Examination of a Beta-Alpha Hybrid Construct of Beta-Hexosaminidase A Subunits, Reported to Interact with the GM2 Activator Protein and Hydrolyze GM2 Ganglioside

2021 ◽  
Author(s):  
Warren W. Wakarchuk ◽  
Incilay Sinici ◽  
Sayuri Yonekawa ◽  
Ilona Tkachyova ◽  
Steven J. Gray ◽  
...  
Keyword(s):  
In Vitro Assays ◽  
Variant Form ◽  
Gm2 Ganglioside ◽  
Activator Protein ◽  
Hexosaminidase A ◽  
Hybrid Construct ◽  
Gm2 Activator ◽  
Gm2 Activator Protein

The hydrolysis in lysosomes of GM2 ganglioside to GM3 ganglioside requires the correct synthesis, intracellular assembly and transport of three separate gene products; i.e., the alpha and beta subunits of heterodimeric beta-hexosaminidase A, E.C. # 3.2.1.52 (encoded by the HEXA and HEXB genes, respectively), and the GM2-activator protein (GM2AP, encoded by the GM2A gene). Mutations in any one of these genes can result in one of three neurodegenerative diseases collectively known as GM2 gangliosidosis (HEXA, Tay-Sachs disease, MIM # 272800; HEXB, Sandhoff disease, MIM # 268800; and GM2A, AB-variant form, MIM # 272750). Elements of both of the hexosaminidase A subunits are needed to productively interact with the GM2 ganglioside-GM2AP complex in the lysosome. Some of these elements have been predicted from the crystal structures of hexosaminidase and the activator. Recently a hybrid of the two subunits has been constructed and reported to be capable of forming homodimers that can perform this reaction in vivo, which could greatly simplify vector-mediated gene transfer approaches for Tay-Sachs or Sandhoff diseases. A cDNA encoding a hybrid hexosaminidase subunit capable of dimerizing and hydrolyzing GM2 ganglioside could be incorporated into a single vector, whereas packaging both subunits of hexosaminidase A into vectors, such as adeno-associated virus, would be impractical due to size constraints. In this report we examine the previously published hybrid construct (H1) and a new more extensive hybrid (H2), with our documented in cellulo (live cell- based) assay utilizing a fluorescent GM2 ganglioside derivative. Unfortunately when Tay-Sachs cells were transfected with either the H1 or H2 hybrid construct and then were fed the GM2 derivative, no significant increase in its turnover was detected. In vitro assays with the isolated H1 or H2 homodimers confirmed that neither was capable of human GM2AP-dependent hydrolysis of GM2 ganglioside.

scholarly journals GM2 activator protein deficiency, mimic of Tay-Sachs disease

2017 ◽  
Vol 04 (02) ◽  
pp. 184-187 ◽  
Author(s):  
Sheena Kochumon ◽  
Dhanya Yesodharan ◽  
KP Vinayan ◽  
Natasha Radhakrishnan ◽  
Jayesh Sheth ◽  
...  
Keyword(s):  
Genetic Disorders ◽  
Molecular Study ◽  
Female Child ◽  
Protein Deficiency ◽  
Rare Type ◽  
Activator Protein ◽  
Intronic Mutation ◽  
Tay Sachs Disease ◽  
Gm2 Activator ◽  
Gm2 Activator Protein

AbstractGM2 Gangliosidoses are a group of autosomal recessive genetic disorders caused by intra-lysosomal deposition of ganglioside GM2 mainly in the neuronal cells. GM2-Activator protein deficiency is an extremely rare type of GM2 gangliosidosis (AB variant) caused by the mutation of GM2A.We report a case of a female child who presented with clinical features similar to classical Tay-Sachs disease, but with normal beta hexosaminidase enzyme levels. Molecular study revealed a novel homozygous intronic mutation which confirmed the diagnosis of GM2 Activator protein deficiency. GM2 Activator protein deficiency is a mimic of Classical Tay-Sachs disease and should be a differential diagnosis in children who present with neuroregression, cherry red spots without hepatosplenomegaly and with normal beta hexosaminidase enzyme levels.

Two patients from Turkey with a novel variant in the GM2A gene and review of the literature

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Aslı İnci ◽  
Filiz Başak Cengiz Ergin ◽  
Gürsel Biberoğlu ◽  
İlyas Okur ◽  
Fatih Süheyl Ezgü ◽  
...  
Keyword(s):  
Sandhoff Disease ◽  
Pathogenic Variant ◽  
Protein Deficiency ◽  
Gm2 Gangliosidosis ◽  
Infantile Form ◽  
Rare Form ◽  
Inborn Errors ◽  
Activator Protein ◽  
Gm2 Activator ◽  
Gm2 Activator Protein

Abstract Objectives GM2 gangliosidosis is a rare form of inborn errors of metabolism including Tay-Sachs disease, Sandhoff disease, and GM2 activator deficiency. GM2 activator protein deficiency is an ultra-rare form of GM2 gangliosidosis. To date, 16 cases of GM2 activator protein deficiency have been reported in the literature, and among them, 11 cases were the infantile form of the disease. Here we report the first two patients from Turkey with the infantile form of the disease with a novel likely pathogenic variant. Case presentation A boy of eight months old presented to the metabolic department with very mild neurological deterioration, although he had achieved early developmental milestones at the appropriate time. The parents also had a daughter who had lost skills progressively before one year of age. The boy was evaluated and bilateral cherry-red spots were found with no abnormality in either metabolic screening including β-hexosaminidase or cranial magnetic resonance imaging. A novel homozygous likely pathogenic variant in GM2A was detected in a next-generation sequence panel revealing GM2 activator protein deficiency. His sister was investigated after he was diagnosed with GM2 activator deficiency and it was found that she had the same variant as her brother. Conclusions This case report emphasizes that in the event of normal β-hexosaminidase activity, GM2 activator protein deficiency could be underdiagnosed, and further molecular analysis should be performed. To the best of our knowledge, this boy is one of the youngest patient diagnosed with very mild symptoms. With this novel pathogenic variant, these patients have expanded the mutation spectrum of GM2 activator protein deficiency.

scholarly journals Stimulation of Interleukin-10 Production by Acidic β-Lactoglobulin-Derived Peptides Hydrolyzed with Lactobacillus paracasei NCC2461 Peptidases

2004 ◽  
Vol 11 (2) ◽  
pp. 266-271 ◽  
Author(s):  
Guénolée Prioult ◽  
Sophie Pecquet ◽  
Ismail Fliss
Keyword(s):  
Oral Tolerance ◽  
Immunosuppressive Agents ◽  
Interleukin 10 ◽  
Lactobacillus Paracasei ◽  
In Vitro Hydrolysis ◽  
Ifn Γ ◽  
Immunomodulatory Peptides ◽  
Β Lactoglobulin

ABSTRACT We have previously demonstrated that Lactobacillus paracasei NCC2461 may help to prevent cow's milk allergy in mice by inducing oral tolerance to β-lactoglobulin (BLG). To investigate the mechanisms involved in this beneficial effect, we examined the possibility that L. paracasei induces tolerance by hydrolyzing BLG-derived peptides and liberating peptides that stimulate interleukin-10 (IL-10) production. L. paracasei peptidases have been shown to hydrolyze tryptic-chymotryptic peptides from BLG, releasing numerous small peptides with immunomodulating properties. We have now shown that acidic tryptic-chymotryptic peptides stimulate splenocyte proliferation and gamma interferon (IFN-γ) production in vitro. Hydrolysis of these peptides with L. paracasei peptidases repressed the lymphocyte stimulation, up-regulated IL-10 production, and down-regulated IFN-γ and IL-4 secretion. L. paracasei NCC2461 may therefore induce oral tolerance to BLG in vivo by degrading acidic peptides and releasing immunomodulatory peptides stimulating regulatory T cells, which function as major immunosuppressive agents by secreting IL-10.

scholarly journals c-Jun N-Terminal Kinase Activation of Activator Protein-1 Underlies Homologous Regulation of the Gonadotropin-Releasing Hormone Receptor Gene in αT3-1 Cells

Endocrinology ◽  
2003 ◽  
Vol 144 (3) ◽  
pp. 839-849 ◽  
Author(s):  
Buffy S. Ellsworth ◽  
Brett R. White ◽  
Ann T. Burns ◽  
Brian D. Cherrington ◽  
Annette M. Otis ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Cell Model ◽  
Receptor Gene ◽  
Critical Role ◽  
Dominant Negative ◽  
Activator Protein 1 ◽  
Activator Protein

Reproductive function is dependent on the interaction between GnRH and its cognate receptor found on gonadotrope cells of the anterior pituitary gland. GnRH activation of the GnRH receptor (GnRHR) is a potent stimulus for increased expression of multiple genes including the gene encoding the GnRHR itself. Thus, homologous regulation of the GnRHR is an important mechanism underlying gonadotrope sensitivity to GnRH. Previously, we have found that GnRH induction of GnRHR gene expression in αT3-1 cells is partially mediated by protein kinase C activation of a canonical activator protein-1 (AP-1) element. In contrast, protein kinase A and a cAMP response element-like element have been implicated in mediating the GnRH response of the GnRHR gene using a heterologous cell model (GGH3). Herein we find that selective removal of the canonical AP-1 site leads to a loss of GnRH regulation of the GnRHR promoter in transgenic mice. Thus, an intact AP-1 element is necessary for GnRH responsiveness of the GnRHR gene both in vitro and in vivo. Based on in vitro analyses, GnRH appeared to enhance the interaction of JunD, FosB, and c-Fos at the GnRHR AP-1 element. Although enhanced binding of cFos reflected an increase in gene expression, GnRH appeared to regulate both FosB and JunD at a posttranslational level. Neither overexpression of a constitutively active Raf-kinase nor pharmacological blockade of GnRH-induced ERK activation eliminated the GnRH response of the GnRHR promoter. GnRH responsiveness was, however, lost in αT3-1 cells that stably express a dominant-negative c-Jun N-terminal kinase (JNK) kinase, suggesting a critical role for JNK in mediating GnRH regulation of the GnRHR gene. Consistent with this possibility, we find that the ability of forskolin and membrane-permeable forms of cAMP to inhibit the GnRH response of the GnRHR promoter is associated with a loss of both JNK activation and GnRH-mediated recruitment of the primary AP-1-binding components.

scholarly journals GM2 Activator Protein.

1997 ◽  
Vol 9 (50) ◽  
pp. 421-432 ◽  
Author(s):  
Yu-Teh Li ◽  
Su-Chen Li
Keyword(s):  
Activator Protein ◽  
Gm2 Activator ◽  
Gm2 Activator Protein

scholarly journals DALAFLOXACIN- ANTIBACTERIAL: A REVIEW

2018 ◽  
Vol 6 (1) ◽  
pp. 91-101
Author(s):  
Bhawana Sain ◽  
Vandana Sharma ◽  
Ashok Kumar Sharma ◽  
Rakesh Goyal ◽  
Mukesh Sharma
Keyword(s):  
Bacterial Infections ◽  
Clinical Symptoms ◽  
Ancient Greek ◽  
Treatment And Prevention ◽  
Beta Hemolytic Streptococcus ◽  
Infected Area ◽  
Multiresistant Strains ◽  
Major Pathogens

Antibiotics (from ancient Greek αντιβιοτικά, antiviotika), also called antibacterials, are a type of antimicrobials drug used in the treatment and prevention of bacterial infections. Cellulitis is an infection that involves the outer layers of the skin. It is commonly caused by bacteria known as beta-hemolytic streptococcus or Staphylococcus aureus. You may experience pain, swelling, tenderness, warmth, and redness in the infected area. Complicate skin and soft tissue infections (SSTIs) are common for both outpatient and hospitalized patients and traditionally include various clinical symptoms ranging from minor superficial infections to necrotizing fasciitis with high rates of mortality. Delafloxacin (DLX) is a new FQ pending approval, which has shown a good in vitro and in vivo activity against major pathogens associated with ABSSSIs and CA-RTIs. It also shows good activity against a broad spectrum of microorganisms, including those resistant to other FQ, and stability against multiresistant strains.

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