Biomedical subjects

R Karry

Publications and source records attributed to R Karry.

4 recordsLinked to original sources

PubMed2005

Antidepressants and prolonged stress in rats modulate CAM-L1, laminin, and pCREB, implicated in neuronal plasticity.

Previously, we reported an ability of NE to promote processes of plasticity in neuroblastoma cells, as observed by morphological changes such as an elongated granule-rich cell body and neuritegenesis, in addition to a progressive decrease in the pluripotent marker Oct4 and an increase in the growth cone marker GAP-43. This was accompanied by the induction of three plasticity genes forming a functional cluster, the cell adhesion molecule L1 (CAM-L1), laminin, and CREB, all involved in neuronal plasticity and neurite outgrowth. In the present study, we hypothesized that the regulation of CAM-L1, laminin, and CREB/pCREB by NE could mediate processes of plasticity in the mode of action of antidepressants, as well as in the long-term effects of stress, in rats, given the association of both with NE alterations and neuronal plasticity. In the first experiment, rats were chronically administered with antidepressants (21 days). In the second experiment, rats were exposed to chronic stress and examined 4 months later, a model shown to exhibit behavioral indices of stress. We found brain region-specific alterations in mRNA and protein levels of CAM-L1, laminin, and pCREB in rats chronically treated with the noradrenergic antidepressant desipramine and, to a lesser extent, in those treated with fluoxetine. Stressed rats presented a decrease in CAM-L1, laminin, and pCREB, specifically in brain areas implicated in stress. Our findings suggest that noradrenergic-regulated plasticity genes such as CAM-L1, laminin, and CREB play an important role both in stress and in the treatment of depression.

Animals↗

PubMed2004

ATF2, a member of the CREB/ATF family of transcription factors, in chronic stress and consequent to antidepressant treatment: animal models and human post-mortem brains.

The regulation of gene expression has been implicated in the etiology and treatment of depression. Transcription factors serve as the intermediates between intracellular cascades and gene expression, and may therefore be involved in the pathophysiology and pharmacotherapy of depression. We and others have previously reported an increase in the phosphorylation of the transcription factor cAMP response element binding protein (CREB) by antidepressants, alongside brain region-specific alterations in pCREB by stress. In the present study, we examined the expression of another member of the CREB/ATF family of transcription factors, ATF2, in the brains of rats chronically treated with two different antidepressants, and in rats 4 months after their exposure to prolonged stress. ATF2 phosphorylation was decreased by antidepressants and increased at the aftermath of prolonged stress, specifically in the frontal cortex. We also examined ATF2 expression in the ventral parieto-occipital region of post-mortem human brains of normal controls, depressed, bipolar, and schizophrenic patients, obtained from the Stanley Foundation Brain Consortium. No alterations were observed in the levels of ATF2. However, in the depressed group, the pATF2 levels were higher in unmedicated compared to medicated patients, suggesting an antidepressant-induced reduction in pATF2. We discuss the possible role of ATF2 in depression, and propose that an interplay between ATF2 and CREB, and possibly other transcription factors, determines the final gene expression pattern in the etiology and treatment of depression.

Activating Transcription Factor 2↗

PubMed2004

Ageing of human epidermis: the role of apoptosis, Fas and telomerase.

BACKGROUND: Aged human epidermis is characterized by morphological changes including flattening of the dermal-epidermal junction and a decrease in thickness. OBJECTIVES: To determine the roles of proliferation, apoptosis, Fas (CD95), Fas ligand (FasL) and telomerase in changes of human epidermis during ageing. METHODS: Human epidermis from aged subjects (n = 14; mean age 70.7 years) and young subjects (n = 14; mean age 23.4 years) was studied by histology, immunohistochemistry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling assay for apoptotic cells and reverse transcription-polymerase chain reaction to determine epidermal thickness, proliferation (Ki-67), apoptosis, expression of Fas and FasL, and telomerase activity. RESULTS: Aged skin was associated with thinning of the epidermis, decreased proliferation, and increased apoptosis below the granular layer. This was associated with increased epidermal expression of Fas and FasL. Telomerase activity was similar in aged and young epidermis. CONCLUSIONS: Fas/FasL-mediated apoptosis, along with decreased proliferation, may have a role in changes of human epidermis during ageing. Telomerase activity did not appear to be limiting in young vs. old human epidermis.

Adolescent↗

PubMed2002

State-dependent alterations in mitochondrial complex I activity in platelets: a potential peripheral marker for schizophrenia.

Schizophrenia, the most severe psychiatric disorder, is characterized by heterogeneity of clinical signs, often categorized into positive and negative symptoms. Among a wide array of competing biological mechanisms, altered cerebral energy metabolism and mitochondrial dysfunction have been suggested to play an important role in the pathophysiology of schizophrenia. In this study we investigated mitochondrial complex I in platelets of 113 schizophrenic patients divided into three groups (acute psychotic episode, chronic active state and residual schizophrenia) and 37 control subjects. Complex I was analysed at the level of enzymatic activity, mRNA and protein levels by enzyme kinetics, RT-PCR and Western blot analyses, respectively. Complex I activity in platelets of schizophrenic patients altered with disease state presenting high specificity and sensitivity. Thus, increased activity was associated with psychotic symptomology, while its decrease was observed in patients with residual schizophrenia. The relationship between the clinical state and complex I activity in schizophrenia was further supported by its positive correlation with the severity of patients' positive symptoms assessed by clinical ratings. In addition, similar alterations were observed at the levels of mRNA and protein of the 24- and 51-kDa iron-sulfur flavoprotein subunits of the complex. Taken together these results point to the potential of platelet complex I to turn into a reliable novel marker for schizophrenia. At present, definitive diagnosis depends only on descriptive behavioral and symptomatic information, therefore a peripheral measurable specific marker will contribute to diagnosis and monitoring of the disease.

Adolescent↗