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Effect of HIV-1-related protein expression on cardiac and skeletal muscles from transgenic rats.

Otis JS, Ashikhmin YI, Brown LA, Guidot DM - AIDS Res Ther (2008)

Bottom Line: We provide compelling experimental evidence that HIV-1-related proteins can lead to significant cardiac and skeletal muscle complications independently of viral infection or replication.Our data support the concept that HIV-1-related proteins are not merely disease markers, but rather have significant biological activity that may lead to increased oxidative stress, the stimulation of redox-sensitive pathways, and altered muscle morphologies.If correct, this pathophysiological scheme suggests that the use of dietary thiol supplements could reduce skeletal and cardiac muscle dysfunction in HIV-1-infected individuals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Pulmonary, Allergy and Critical Care Medicine, Atlanta VA Medical Center and Emory University School of Medicine, 1670 Clairmont Road, Decatur, GA 30033, USA. jsotis@emory.edu

ABSTRACT

Background: Human immunodeficiency virus type 1 (HIV-1) infection and the consequent acquired immunodeficiency syndrome (AIDS) has protean manifestations, including muscle wasting and cardiomyopathy, which contribute to its high morbidity. The pathogenesis of these myopathies remains partially understood, and may include nutritional deficiencies, biochemical abnormalities, inflammation, and other mechanisms due to viral infection and replication. Growing evidence has suggested that HIV-1-related proteins expressed by the host in response to viral infection, including Tat and gp120, may also be involved in the pathophysiology of AIDS, particularly in cells or tissues that are not directly infected with HIV-1. To explore the potentially independent effects of HIV-1-related proteins on heart and skeletal muscles, we used a transgenic rat model that expresses several HIV-1-related proteins (e.g., Tat, gp120, and Nef). Outcome measures included basic heart and skeletal muscle morphology, glutathione metabolism and oxidative stress, and gene expressions of atrogin-1, muscle ring finger protein-1 (MuRF-1) and Transforming Growth Factor-beta1 (TGFbeta1), three factors associated with muscle catabolism.

Results: Consistent with HIV-1 associated myopathies in humans, HIV-1 transgenic rats had increased relative heart masses, decreased relative masses of soleus, plantaris and gastrocnemius muscles, and decreased total and myosin heavy chain type-specific plantaris muscle fiber areas. In both tissues, the levels of cystine (Cyss), the oxidized form of the anti-oxidant cysteine (Cys), and Cyss:Cys ratios were significantly elevated, and cardiac tissue from HIV-1 transgenic rats had altered glutathione metabolism, all reflective of significant oxidative stress. In HIV-1 transgenic rat hearts, MuRF-1 gene expression was increased. Further, HIV-1-related protein expression also increased atrogin-1 (approximately 14- and approximately 3-fold) and TGFbeta1 (approximately 5-fold and approximately 3-fold) in heart and plantaris muscle tissues, respectively.

Conclusion: We provide compelling experimental evidence that HIV-1-related proteins can lead to significant cardiac and skeletal muscle complications independently of viral infection or replication. Our data support the concept that HIV-1-related proteins are not merely disease markers, but rather have significant biological activity that may lead to increased oxidative stress, the stimulation of redox-sensitive pathways, and altered muscle morphologies. If correct, this pathophysiological scheme suggests that the use of dietary thiol supplements could reduce skeletal and cardiac muscle dysfunction in HIV-1-infected individuals.

No MeSH data available.


Related in: MedlinePlus

Atrogin-1, MuRF-1 and TGFβ1 mRNA expression patterns in cardiac and plantaris tissues from HIV-1 transgenic rats. Gene expression levels of several catabolic factors including, atrogin-1, MuRF-1 and TGFβ1, were markedly increased in HIV-1 transgenic rat heart tissues compared to controls (A-C, respectively). Similarly, mRNA expression levels of atrogin-1 and TGFβ1 were increased in plantaris muscles from HIV-1 transgenic rats compared to controls (D and F, respectively), however, no changes were detected in the levels of MuRF-1 (E). *, p ≤ 0.05 vs. control.
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Figure 4: Atrogin-1, MuRF-1 and TGFβ1 mRNA expression patterns in cardiac and plantaris tissues from HIV-1 transgenic rats. Gene expression levels of several catabolic factors including, atrogin-1, MuRF-1 and TGFβ1, were markedly increased in HIV-1 transgenic rat heart tissues compared to controls (A-C, respectively). Similarly, mRNA expression levels of atrogin-1 and TGFβ1 were increased in plantaris muscles from HIV-1 transgenic rats compared to controls (D and F, respectively), however, no changes were detected in the levels of MuRF-1 (E). *, p ≤ 0.05 vs. control.

Mentions: Using a model of chronic alcohol ingestion to induce oxidative stress in skeletal muscle, we have recently identified atrogin-1 and TGFβ1 as redox-sensitive catabolic factors [11]. However, whether or not these factors or MuRF-1 were also sensitive to HIV-1-related protein-induced oxidative stress was unknown. Atrogin-1 levels increased ~14- and ~3-fold in heart and plantaris muscles from HIV-1 transgenic rats, respectively (Figures 4A and 4D). Interestingly, MuRF-1 mRNA levels were only increased in HIV-1 transgenic rat hearts (Figure 4B). Gene levels of TGFβ1 were increased ~5- and ~3-fold in heart and plantaris muscles from HIV-1 transgenic rats, respectively (Figures 4C and 4F).


Effect of HIV-1-related protein expression on cardiac and skeletal muscles from transgenic rats.

Otis JS, Ashikhmin YI, Brown LA, Guidot DM - AIDS Res Ther (2008)

Atrogin-1, MuRF-1 and TGFβ1 mRNA expression patterns in cardiac and plantaris tissues from HIV-1 transgenic rats. Gene expression levels of several catabolic factors including, atrogin-1, MuRF-1 and TGFβ1, were markedly increased in HIV-1 transgenic rat heart tissues compared to controls (A-C, respectively). Similarly, mRNA expression levels of atrogin-1 and TGFβ1 were increased in plantaris muscles from HIV-1 transgenic rats compared to controls (D and F, respectively), however, no changes were detected in the levels of MuRF-1 (E). *, p ≤ 0.05 vs. control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2365956&req=5

Figure 4: Atrogin-1, MuRF-1 and TGFβ1 mRNA expression patterns in cardiac and plantaris tissues from HIV-1 transgenic rats. Gene expression levels of several catabolic factors including, atrogin-1, MuRF-1 and TGFβ1, were markedly increased in HIV-1 transgenic rat heart tissues compared to controls (A-C, respectively). Similarly, mRNA expression levels of atrogin-1 and TGFβ1 were increased in plantaris muscles from HIV-1 transgenic rats compared to controls (D and F, respectively), however, no changes were detected in the levels of MuRF-1 (E). *, p ≤ 0.05 vs. control.
Mentions: Using a model of chronic alcohol ingestion to induce oxidative stress in skeletal muscle, we have recently identified atrogin-1 and TGFβ1 as redox-sensitive catabolic factors [11]. However, whether or not these factors or MuRF-1 were also sensitive to HIV-1-related protein-induced oxidative stress was unknown. Atrogin-1 levels increased ~14- and ~3-fold in heart and plantaris muscles from HIV-1 transgenic rats, respectively (Figures 4A and 4D). Interestingly, MuRF-1 mRNA levels were only increased in HIV-1 transgenic rat hearts (Figure 4B). Gene levels of TGFβ1 were increased ~5- and ~3-fold in heart and plantaris muscles from HIV-1 transgenic rats, respectively (Figures 4C and 4F).

Bottom Line: We provide compelling experimental evidence that HIV-1-related proteins can lead to significant cardiac and skeletal muscle complications independently of viral infection or replication.Our data support the concept that HIV-1-related proteins are not merely disease markers, but rather have significant biological activity that may lead to increased oxidative stress, the stimulation of redox-sensitive pathways, and altered muscle morphologies.If correct, this pathophysiological scheme suggests that the use of dietary thiol supplements could reduce skeletal and cardiac muscle dysfunction in HIV-1-infected individuals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Pulmonary, Allergy and Critical Care Medicine, Atlanta VA Medical Center and Emory University School of Medicine, 1670 Clairmont Road, Decatur, GA 30033, USA. jsotis@emory.edu

ABSTRACT

Background: Human immunodeficiency virus type 1 (HIV-1) infection and the consequent acquired immunodeficiency syndrome (AIDS) has protean manifestations, including muscle wasting and cardiomyopathy, which contribute to its high morbidity. The pathogenesis of these myopathies remains partially understood, and may include nutritional deficiencies, biochemical abnormalities, inflammation, and other mechanisms due to viral infection and replication. Growing evidence has suggested that HIV-1-related proteins expressed by the host in response to viral infection, including Tat and gp120, may also be involved in the pathophysiology of AIDS, particularly in cells or tissues that are not directly infected with HIV-1. To explore the potentially independent effects of HIV-1-related proteins on heart and skeletal muscles, we used a transgenic rat model that expresses several HIV-1-related proteins (e.g., Tat, gp120, and Nef). Outcome measures included basic heart and skeletal muscle morphology, glutathione metabolism and oxidative stress, and gene expressions of atrogin-1, muscle ring finger protein-1 (MuRF-1) and Transforming Growth Factor-beta1 (TGFbeta1), three factors associated with muscle catabolism.

Results: Consistent with HIV-1 associated myopathies in humans, HIV-1 transgenic rats had increased relative heart masses, decreased relative masses of soleus, plantaris and gastrocnemius muscles, and decreased total and myosin heavy chain type-specific plantaris muscle fiber areas. In both tissues, the levels of cystine (Cyss), the oxidized form of the anti-oxidant cysteine (Cys), and Cyss:Cys ratios were significantly elevated, and cardiac tissue from HIV-1 transgenic rats had altered glutathione metabolism, all reflective of significant oxidative stress. In HIV-1 transgenic rat hearts, MuRF-1 gene expression was increased. Further, HIV-1-related protein expression also increased atrogin-1 (approximately 14- and approximately 3-fold) and TGFbeta1 (approximately 5-fold and approximately 3-fold) in heart and plantaris muscle tissues, respectively.

Conclusion: We provide compelling experimental evidence that HIV-1-related proteins can lead to significant cardiac and skeletal muscle complications independently of viral infection or replication. Our data support the concept that HIV-1-related proteins are not merely disease markers, but rather have significant biological activity that may lead to increased oxidative stress, the stimulation of redox-sensitive pathways, and altered muscle morphologies. If correct, this pathophysiological scheme suggests that the use of dietary thiol supplements could reduce skeletal and cardiac muscle dysfunction in HIV-1-infected individuals.

No MeSH data available.


Related in: MedlinePlus