A role of the thymus and thymosin-α1 in brain NGF levels and NGF receptor expression

Turrini, Paolo; Tirassa, Paola; Vigneti, Eliana; Aloe, Luigi

doi:10.1016/s0165-5728(97)00189-6

Cited by 17 publications

(14 citation statements)

References 48 publications

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“…Interestingly, the L1 expression level declined at 10 lg/ ml Tb4 treatment concentration. We speculated that Tb4 was involved in regulation of L1 expression by negative feedback mechanism, which is similar to previous studies about Thymosin-a1 regulating brain NGF synthesis [67]. We know, actin in the neurons is concentrated in the region of synapse, dendritic spines and terminals, and many neuronal physiological functions including peptide synthesis are accompanied by the disassembly of cellular b-actin cytoskeleton.…”

Section: Discussionsupporting

confidence: 78%

The Promotive Effects of Thymosin β4 on Neuronal Survival and Neurite Outgrowth by Upregulating L1 Expression

et al. 2008

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Thymosin beta(4) (Tbeta4) is a major actin-sequestering peptide widely distributed in mammalian tissues including the nervous system. The presence of this peptide in the nervous system likely plays a role in synaptogensis, axon growth, cell migration, and plastic changes in dendritic spine. However, the effects of Tbeta4 on the survival of neurons and axonal outgrowth have still not been fully understood. So far it is not clear if the effects of Tbeta4 are associated with L1 functions. In the present study, we hypothesized that Tbeta4-induced up-regulation of L1 synthesis could be involved in the survival and axon outgrowth of cultured spinal cord neurons. To test this hypothesis, primarily cultured neurons were prepared from the mouse spinal cord and treated with various concentrations of Tbeta4 ranging from 0.1 to 10 microg/ml. The analysis of L1 mRNA expression and protein synthesis in neurons was then carried out using RT-PCR and western blot assays, respectively. After the addition of Tbeta4 to cultures, cells were then treated with antibodies against distinct domains of L1-Fc. Subsequently, beta-tubulin III and L1 double-labeled indirect immunofluorescence was carried out. Meanwhile, L1 immunofluorescent reactivity was analyzed and compared in cells treated with Tbeta4. Furthermore, the number of beta-tubulin III-positive cells and neurite lengths were measured. We found that Tbeta4 enhanced L1 expression in a dose-dependent manner, and the highest L1 mRNA and protein synthesis in cells increased by more than 2.1- and 2.3-fold in the presence of Tbeta4 at identical concentrations, respectively. Moreover, it also dose dependently enhanced neurite outgrowth and neuronal survival. Compared to conditions without Tbeta4, the length of neurite and neuronal survival increased markedly in presence of 0.5, 1, and 5 microg/ml Tbeta4, respectively, whereas the effects of Tbeta4 were significantly attenuated or inhibited in the process of L1-Fc antibodies treatment. These above results indicate that the promotive effect of Tbeta4 on the survival and neurite outgrowth of cultured spinal cord neurons might be mediated, at least in part via a stimulation of the production of L1 in the neurons.

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Section: Discussionsupporting

confidence: 78%

The Promotive Effects of Thymosin β4 on Neuronal Survival and Neurite Outgrowth by Upregulating L1 Expression

et al. 2008

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“…Thymosins, one family of thymic hormones, play a crucial role in the development and maintenance of a competent immune system, especially in the differentiation and maturation of T-lymphocytes [1], [2], [3], [4]. Thymosins (THY) were originally isolated and purified from calf thymus by Goldstein and White in 1966 [5].…”

Section: Introductionmentioning

confidence: 99%

Molecular Characterization, Tissue Distribution, Subcellular Localization and Actin-Sequestering Function of a Thymosin Protein from Silkworm

Zhang

et al. 2012

PLoS ONE

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We identified a novel gene encoding a Bombyx mori thymosin (BmTHY) protein from a cDNA library of silkworm pupae, which has an open reading frame (ORF) of 399 bp encoding 132 amino acids. It was found by bioinformatics that BmTHY gene consisted of three exons and two introns and BmTHY was highly homologous to thymosin betas (Tβ). BmTHY has a conserved motif LKHTET with only one amino acid difference from LKKTET, which is involved in Tβ binding to actin. A His-tagged BmTHY fusion protein (rBmTHY) with a molecular weight of approximately 18.4 kDa was expressed and purified to homogeneity. The purified fusion protein was used to produce anti-rBmTHY polyclonal antibodies in a New Zealand rabbit. Subcellular localization revealed that BmTHY can be found in both Bm5 cell (a silkworm ovary cell line) nucleus and cytoplasm but is primarily located in the nucleus. Western blotting and real-time RT-PCR showed that during silkworm developmental stages, BmTHY expression levels are highest in moth, followed by instar larvae, and are lowest in pupa and egg. BmTHY mRNA was universally distributed in most of fifth-instar larvae tissues (except testis). However, BmTHY was expressed in the head, ovary and epidermis during the larvae stage. BmTHY formed complexes with actin monomer, inhibited actin polymerization and cross-linked to actin. All the results indicated BmTHY might be an actin-sequestering protein and participate in silkworm development.

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“…Although the primary target of this virus is the immune system, neurological abnormalities are common in patients infected with HIV (Bean 2001). The immune system and central nervous system (CNS), once considered completely independent, have been demonstrated to be closely linked (Dalakas et al 1986; Fabris et al 1988; Spangelo 1995; Antoniou et al 1997; Turrini et al 1998; Savino and Dardenne 2000; Nishiyama 2001; Morale et al 2003; Cavalloti et al 2005; Fleming et al 2005). Bidirectional communication between the brain and the thymus has been described in numerous studies, in association with cytokines, hormones, growth factors, and neurotransmitters (Fabris et al 1988; Antoniou et al 1997; Morale et al 2003; Cavalloti et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Cognitive performance and the thymus among HIV-infected subjects receiving HAART

Míguez‐Burbano

Lewis

Moreno

et al. 2008

BTT

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Objective:To evaluate the impact of alcohol use, which is widespread in human immunodeficiency virus (HIV)+ individuals, on highly active antiretroviral therapy (HAART)-associated immune and cognitive improvements and the relationship between those two responses.Methods:In a case-control longitudinal study, thymic volume, cognition, and immune responses were evaluated at baseline and after 6 months therapy in HIV+ and HIV- controls. Cognitive performance was evaluated using the HIV Dementia Score (HDS) and the California Verbal Learning Test (CVLT).Results:Prior to HAART, thymic volume varied considerably from 2.7 to 29.3 cm3 (11 ± 7.2 cm3). Thymic volume at baseline showed a significantly inverse correlation with the patient’s number of years of drinking (r2 = 0.207; p < 0.01), as well as HDS and the CVLT scores in both HIV-infected (r2 = 0.37, p = 0.03) and noninfected (r2 = 0.8, p < 0.01). HIV-infected individuals with a small thymic volume scored in the demented range, as compared with those with a larger thymus (7 ± 2.7 vs. 12 ± 2.3, p = 0.005). After HAART, light/moderate drinkers exhibited thymus size twice that of heavy drinkers (14.8 ± 10.4 vs. 6.9 ± 3.3 cm3).Conclusions:HAART-associated increases of thymus volume appear to be negatively affected by alcohol consumption and significantly related to their cognitive status. This result could have important clinical implications.

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A role of the thymus and thymosin-α1 in brain NGF levels and NGF receptor expression

Cited by 17 publications

References 48 publications

The Promotive Effects of Thymosin β4 on Neuronal Survival and Neurite Outgrowth by Upregulating L1 Expression

The Promotive Effects of Thymosin β4 on Neuronal Survival and Neurite Outgrowth by Upregulating L1 Expression

Molecular Characterization, Tissue Distribution, Subcellular Localization and Actin-Sequestering Function of a Thymosin Protein from Silkworm

Cognitive performance and the thymus among HIV-infected subjects receiving HAART

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