Insight into Calcium-Binding Motifs of Intrinsically Disordered Proteins.

Motifs within proteins help us categorize their functions. Intrinsically disordered proteins (IDPs) are rich in short linear motifs, conferring them many different roles. IDPs are also frequently highly charged and, therefore, likely to interact with ions. Canonical calcium-binding motifs, such as the EF-hand, often rely on the formation of stabilizing flanking helices, which are a key characteristic of folded proteins, but are absent in IDPs. In this study, we probe the existence of a calcium-binding motif relevant to IDPs. Upon screening several carefully selected IDPs using NMR spectroscopy supplemented with affinity quantification by colorimetric assays, we found calcium-binding motifs in IDPs which could be categorized into at least two groups-an Excalibur-like motif, sequentially similar to the EF-hand loop, and a condensed-charge motif carrying repetitive negative charges. The motifs show an affinity for calcium typically in the ~100 µM range relevant to regulatory functions and, while calcium binding to the condensed-charge motif had little effect on the overall compaction of the IDP chain, calcium binding to Excalibur-like motifs resulted in changes in compaction. Thus, calcium binding to IDPs may serve various structural and functional roles that have previously been underreported.

Brain is an endocrine organ through secretion and nuclear transfer of parathymosin.

This study reports that parathymosin (PTMS) is secreted by hypothalamic stem/progenitor cells (htNSC) to inhibit senescence of recipient cells such as fibroblasts. Upon release, PTMS is rapidly transferred into the nuclei of various cell types, including neuronal GT1-7 cells and different peripheral cells, and it is effectively transferred into neuronal nuclei in various brain regions in vivo. Notably, brain neurons also produce and release PTMS, and because neuronal populations are large, they are important for maintaining PTMS in the cerebrospinal fluid which is further transferable into the blood. Compared with several other brain regions, the hypothalamus is stronger for long-distance PTMS transfer, supporting a key hypothalamic role in this function. In physiology, aging is associated with declines in PTMS production and transfer in the brain, and ptms knockdown in the hypothalamus versus hippocampus were studied showing different contributions to neurobehavioral physiology. In conclusion, the brain is an endocrine organ through secretion and nuclear transfer of PTMS, and the hypothalamus-brain orchestration of this function is protective in physiology and counteractive against aging-related disorders.

Immunopotentiator Thymosin Alpha-1 Promotes Neurogenesis and Cognition in the Developing Mouse via a Systemic Th1 Bias.

In early life, the immune system plays an essential role in brain development. In our study, the immunopotentiator thymosin alpha-1 (Ta1) was peripherally administered to neonatal mice to explore whether the peripheral immunopotentiator affects neurodevelopment and cognition, and to further investigate the relevant mechanism. Compared with the control group, the Ta1 mice displayed better cognitive abilities in early life. The numbers of 5-bromodeoxyuridine (BrdU)+, nestin+, T-box transcription factor 2 (Tbr2)+, BrdU+/doublecortin (DCX)+, BrdU+/ionized calcium-binding adaptor molecule 1 (Iba1)+, and BrdU+/neuronal nuclei (NeuN)+ cells in the hippocampus were increased in the Ta1 group, accompanied by increased interleukin-4 (IL-4), interferon-gamma, brain-derived neurotrophic factor, nerve growth factor, and insulin-like growth factor-1 as well as decreased IL-6 and tumor necrosis factor-α. Furthermore, the Ta1-group showed a Th1-polarized immune response, and the neurotrophic factors were positively associated with the Th1/Th2 ratio. More importantly, administration of Ta1 blocked lipopolysaccharide-induced impairment of hippocampal neurogenesis in early life. These findings suggest that peripheral Ta1 contributes to neurogenesis and cognition probably through a systemic Th1 bias, as well as neuroprotection against LPS infection by Ta1.

Thymosin α1 represents a potential potent single-molecule-based therapy for cystic fibrosis.

Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) that compromise its chloride channel activity. The most common mutation, p.Phe508del, results in the production of a misfolded CFTR protein, which has residual channel activity but is prematurely degraded. Because of the inherent complexity of the pathogenetic mechanisms involved in CF, which include impaired chloride permeability and persistent lung inflammation, a multidrug approach is required for efficacious CF therapy. To date, no individual drug with pleiotropic beneficial effects is available for CF. Here we report on the ability of thymosin alpha 1 (Tα1)-a naturally occurring polypeptide with an excellent safety profile in the clinic when used as an adjuvant or an immunotherapeutic agent-to rectify the multiple tissue defects in mice with CF as well as in cells from subjects with the p.Phe508del mutation. Tα1 displayed two combined properties that favorably opposed CF symptomatology: it reduced inflammation and increased CFTR maturation, stability and activity. By virtue of this two-pronged action, Tα1 has strong potential to be an efficacious single-molecule-based therapeutic agent for CF.

[Effect of Acupuncture on Prognosis and Immune Function of Sepsis Patients].

OBJECTIVE: To study the effect of acupuncture on the immune function of sepsis patients. METHODS: Ninety sepsis patients were assigned to the control group, the thymosin a1 group, and the acupuncture treatment group according to random digit table, 30 patients in each group. Patients in the control group were treated according to the guideline of Surviving Sepsis Campaign (SSC). Patients in the control group received routine treatment. Those in the thymosin alpha1 group additionally received subdermal injection of thymosin alpha1 (1.6 mg), once per day for 6 successive days. Needling at related points such as Zusanli (ST36), Yanglingquan (GB34), Neiguan (PC6), Guanyuan (RN4), and so on, was performed in patients of the acupuncture treatment group, once per day for 6 successive days. T cell subgroups (CD3+, CD4+, CD8+, CD4+ /CD8+) and immunoglobulin levels (IgG, IgA, IgM) were detected. The length of ICU hospital stay, hospital readmission rate, and 28-day mortality were compared among the three groups. RESULTS: After six days of treatment, CD3+, CD4+, CD8+, IgG, IgA, IgM, and CD4+ /CD8+ ratio of three groups were all significantly increased (P < 0.01). Of them, CD3+, CD4+, CD8+, IgG, IgA, and IgM increased more significantly in the thymosin alpha1 group and the acupuncture treatment group (P < 0.01). Compared with the control group, the ICU hospitalization length was significantly shortened, the hospital readmission rate and the 28-day mortality were lower in the thymosin alpha1 group and the acupuncture treatment group (P < 0.05, P < 0.01). There was no statistical difference in each index between the thymosin alpha1 group and the acupuncture treatment group (P > 0.05). CONCLUSION: Acupuncture could adjust the immune function of sepsis patients, improve their immunological indicators and prognoses.

Efficacy of thymosin α1 and interferon α for the treatment of severe acute pancreatitis in a rat model.

The present study aimed to investigate the effects of treatment with thymosin α1 (TA1) or interferon α (IFNα) following the establishment of severe acute pancreatitis (SAP) in rats. A total of 144 Sprague­Dawley rats were randomly divided into four groups. The rats in all four groups were celiotomized, and the rats in the control group were administered with an intravenous injection of saline. The three other groups were administered with 5% 1 ml/kg sodium taurocholate via the cholangiopancreatic duct. SAP group rats were administered with an intravenous injection of saline; TA1 group rats received 26.7 µg/kg TA1; and interferon α (INFα) group rats received 4.0x105 U/kg IFNα. The rats were anesthetized and blood samples were collected from the animals 3, 12 and 24 h after surgery. The levels of T cell subsets, serum enzyme indicators, cytokines and procalcitonin (PCT) were measured. The general conditions of the rats were observed until sacrifice, and pancreatic and lung tissue samples were sampled for hematoxylin and eosin staining and histological scoring. The expression levels of aspartate transaminase, lactate dehydrogenase, α­amylase (AMY), P­type­amylase, lipase, PCT, tumor­necrosis factor α, interleukin (IL)­4, IL­5, and IL­18 in the TA1 and IFNα­treated rats were significantly lower, compared with those of the SAP rats within the first 24 h of model establishment (P<0.05). The TA1 and IFNα­treated rats exhibited significantly increased levels of CD3+, CD4+ and CD8+ T cells, and an increased ratio of CD4+/CD8+ cells, compared with SAP rats. Histological analysis revealed that the TA1 and IFNα­treated rats exhibited significantly ameliorated pancreas and lung damage, and mortality rates were reduced from 50.0% (6/12) to 25.0% (3/12) and 33.3% (4/12), respectively. The immunomodulatory agents TA1 and IFNα reduced acute inflammation, decreasing cell damage and enhancing immune function and survival rates in the SAP rats.

Historical review on thymosin α1 in oncology: preclinical and clinical experiences.

INTRODUCTION: Thymosin α1 (Tα1) is a naturally occurring polypeptide that regulates immune cell development and function, and is also capable of interacting with multiple target cells with relevant biological effects. The rationale of Tα1 use in cancer treatment stems from the consideration that tumor progression is favored by a failure of the immune response and in turn induces immune suppression. This paper will review the historical background of Tα1 use in oncology, aiming to highlight the importance of Tα1 as an immunotherapeutic tool to be used in combination with chemotherapy, a concept that is not yet fully established in clinic. AREAS COVERED: The efficacy and safety of combining Tα1 with chemotherapy and cytokines were first evaluated in murine tumor models, providing essential information about effects, mechanisms of action, doses and treatment protocols. The therapeutic potential of the chemo-immunotherapy protocol on metastatic melanoma and lung cancer has been confirmed in controlled clinical trials. Critical for the efficacy of the chemo-immunotherapy protocol is the dual action of Tα1 on immune effector and tumor cells. EXPERT OPINION: On the basis of the preclinical and clinical results available, the use of the chemo-immunotherapy protocol, in which the role of Tα1 is central, is strongly recommended.

Evaluation of thymosin α 1 in nonclinical models of the immune-suppressing indications melanoma and sepsis.

OBJECTIVES: Recent understanding of the complex pathophysiology of melanoma and severe sepsis suggests that immune-modulating compounds such as thymosin alpha 1 (INN: thymalfasin; abbreviated Ta1) could be useful in the treatment of these two unrelated immune-suppressing indications. RESEARCH DESIGN AND METHODS: Three nonclinical murine models were utilized, including: i) a lung metastasis B16 model; ii) a B16-based tumor growth model; and iii) a cecal-ligation and puncture (CLP) sepsis model. RESULTS: In the lung metastasis model, Ta1 treatment alone led to a 32% decrease in metastases (p < 0.05). Additionally, combinations of Ta1 and an anti-PD-1 antibody led to significantly fewer metastases than vehicle. In the tumor growth model, significant decreases in tumor growth were seen: 34% (p = 0.015) to 46% (p = 0.001) depending on the Ta1 dose. In the CLP sepsis model, Ta1 treatment showed a positive trend towards increased survival and decreased bacterial load. In this CLP model, Ta1 also appeared to have an effect on the levels of some biomarkers. CONCLUSIONS: All three models demonstrated a benefit after treatment with Ta1, with no evidence of toxicity. These initial pilot studies support the hypothesis that immune-suppressive indications, including sepsis and melanoma, may be treated with Ta1 alone or by Ta1 in combination with other immunotherapies.

Phyllanthus species versus antiviral drugs for chronic hepatitis B virus infection.

BACKGROUND: Phyllanthus species for patients with chronic hepatitis B virus (HBV) infection have been assessed in clinical trials, but no consensus regarding their usefulness exists. When compared with placebo or no intervention, we were unable to identify convincing evidence that phyllanthus species are beneficial in patients with chronic hepatitis B. Some randomised clinical trials have compared phyllanthus species versus antiviral drugs. OBJECTIVES: To evaluate the benefits and harms of phyllanthus species compared with antiviral drugs for patients with chronic HBV infection. SEARCH METHODS: Searches were performed in The Cochrane Hepato-Biliary Gorup Controlled Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expended, and the Chinese Biomedical CD Database, China Network Knowledge Information, Chinese Science Journal Database, TCM Online, and Wanfang Database. Conference proceedings in Chinese were handsearched. All searches were conducted until 31st October 2012. SELECTION CRITERIA: Randomised clinical trials comparing phyllanthus species with antiviral drugs for patients with chronic HBV infection. We included trials irrespective of blinding, publication status, or language. DATA COLLECTION AND ANALYSIS: Two authors selected the trials and extracted the data independently. The RevMan software was used for statistical analysis of dichotomous data with risk ratio (RR) with 95% confidence intervals (CI). We assessed the risk of bias to control for systematic errors. We calculated the number of patients needed (required information size) to be randomised in order to make reliable conclusions. We assessed the cumulative findings with trial sequential analysis to control for random errors. MAIN RESULTS: We identified five randomised clinical trials with 290 patients. All trials were considered to have high risk of bias. Patients in the experimental group received compound phyllanthus for three months to 12 months. Patients in the antiviral drug group received lamivudine, interferon alpha, thymosin, or thymosin alpha 1. None of the trials reported mortality, hepatitis B-related morbidity, quality of life, or liver histology. Phyllanthus seemed to have a superior effect on clearance of serum HBeAg at the end of treatment in conventional meta-analysis (RR 0.76; 95% CI 0.64 to 0.91, P = 0.002; I(2) = 0%), but not when trial sequential analysis was applied. Phyllanthus had no significant effect on clearance of serum HBsAg (RR 1.00; 95% CI 0.93 to 1.08, P = 0.92; I(2) = 0%) or HBV DNA (RR 0.83; 95% CI 0.53 to 1.31, P = 0.43; I(2) = 70%) when compared with antiviral drugs. Data on HBeAg seroconversion was reported in one trial and no significant difference was found comparing phyllanthus versus lamivudine (RR 0.89; 95% CI 0.71 to 1.11). No data were reported on adverse events in the five trials. AUTHORS' CONCLUSIONS: There is currently insufficient evidence to support or refute the use of phyllanthus for patients with chronic hepatitis B virus infection. Researchers who are interested in conducting further randomised clinical trials on phyllanthus ought to monitor both beneficial and harmful effects and should primarily test the herb against placebo in addition to antiviral drugs that are known to offer more benefit than harm. Only in this way new interventions can be assessed without compromising personal ethical considerations.

[The influence of pulsed infrared laser radiation on the hormone production in the thymus (an experimental study)].

Local irradiation with pulsed (1500 Hz) low-energy infrared laser light of the thymus and thyroid gland region caused well-apparent stimulation of alpha-1-thymosin production in the healthy animals and normalized its level in the stressed ones. Similar stimulation of alpha-1-timosine biosynthesis was observed in an experiment with direct laser irradiation of the cultured HTSC epitheliocytes from the human thymus.

Immunological modifications during treatment with thymosin alpha1 plus antiviral therapy in chronic hepatitis C.

The current standard therapy for the treatment of chronic hepatitis C virus (HCV) is the combination of peginterferon and ribavirin, although many patients fail to clear the virus and their retreatment options are still unsatisfactory. Thymosin alpha1 (Talpha1) is an immunomodulating agent that has been proposed as complementary therapy for chronic HCV, especially in the setting of difficult-to-treat patients. The aim of this study was to evaluate, in patients nonresponsive to previous Peg-based therapy, the effect of standard antiviral therapy with or without Talpha1 on peripheral lymphocyte subsets. Twenty-four patients, 12 receiving Talpha1 and 12 standard therapy, were enrolled. Peripheral subpopulations were analyzed by flow cytometry. Although the addition of Talpha1 did not seem to significantly modify the T-lymphocyte subpopulations, as comparable behaviors were observed in the CD4 and CD8 longitudinal evaluation, Talpha1 produced an earlier increase of natural killer cells. An accurate selection of HCV patients who can benefit from immunomodulation is needed.

Intraperitoneal co-administration of thymosin alpha-1 ameliorates streptozotocin-induced pancreatic lesions and diabetes in C57BL/6 mice.

We investigated the effects of the in vivo administration of thymosin alpha-1 (Talpha-1) on streptozotocin (STZ)-induced pancreatic lesions and diabetes. Mice were randomly divided into four experimental groups: normoglycemic control, STZ-treated, STZ plus 0.1 microg/kg body weight/day Talpha-1-treated, and STZ plus 1 microg/kg/day Talpha-1-treated. Blood glucose was assayed periodically, and serum insulin was determined at the end of the experiment using the ELISA Kit. Aldehyde fuchsin staining was used for histopathological examination of the pancreas. Parameters for oxidative stress were measured with pancreatic malondialdehyde (MDA) level, glutathione (GSH) content and enzymatic activities of superoxide dismutase and catalase. Fourteen days after the initiation of Talpha-1 treatment and up to day 35 when the treatment was stopped, both of the two STZ and Talpha-1-co-treated mouse groups had significant lower levels of blood glucose than the STZ-treated but Talpha-1-untreated mice, although both remained higher than that of the normoglycemic controls. At the end of the Talpha-1 treatment, the serum insulin level for STZ-treated mice receiving 1 microg/kg/day Talpha-1 for 35 days was 2-fold (P<0.001) as much as that of the Talpha-1-untreated STZ-diabetic mice, although not completely restored to the normal level. Pancreatic aldehyde fuchsin staining showed that STZ treatment caused significant pancreatitis, islet atrophy, and a significant reduction in the number of pancreatic beta cells. These histological lesions, however, were significantly alleviated by 1 microg/kg/day Talpha-1 treatment for 35 days. Furthermore, compared with the Talpha-1- untreated STZ-diabetic mice, the pancreatic GSH level of the 1 microg/kg/day Talpha-1-treated STZ-induced mice was 1.92-fold that of the untreated STZ-induced mice (P<0.01), whereas the pancreatic MDA level was only 81.9% that of the untreated STZ-diabetic mice (P<0.05). Together these results demonstrate that co-administration of Talpha-1 leads to significant protection against STZ-induced pancreatic damage and diabetes, and part of the protection might be achieved through enhancing pancreatic antioxidative capability.

[Clinical trial with a new immunomodulatory strategy: treatment of severe sepsis with Ulinastatin and Maipuxin].

OBJECTIVE: To evaluate the efficacy of treatment of severe sepsis by combining anti-inflammatory and immune-enhancing agents. METHODS: Multiple-center, prospective, randomized, controlled designs. Cases were from surgical or general ICU of 26 university teaching hospitals. Totally, 433 adult patients developing severe sepsis with Marshall score 5-20 were enrolled. Patients received either standard treatment based on SSC direction (as group control), or additional Ulinastatin (urinary trypsin inhibitor) 300 K units per day+thymosin alpha1 (Maipuxin) 1.6 mg per day for 7 days (as treatment group 1, adopted in the first trial), or double dosage of the above agents (as treatment group 2, adopted in the second trial). The outcome of 28 and 90 days, APACHEII and Marshall score, monocyte HLA-DR/CD14+ at several points until 28 days, and the lengths of ICU stay, antibiotics usage and mechanical ventilation were determinated. RESULTS: In the first trial (91 cases), there was no significant difference in variables between treatment group 1 and control at 28 days. In the second trial (342 cases), the mortality of treatment group 2 decreased from 38.32% to 25.14% (P=0.0088), compared with group control at 28 days, and from 52.10% to 37.14% (P=0.0054) on 90 days. APACHEIIalso decreased from 14.32 to 12.70 (P=0.0384) and monocyte HLA-DR/CD14+ increased from 40.13% to 51.65% (P=0.0092) on 28 days in treatment group 2. Other variables had no significant differences between two groups. CONCLUSION: Treatment by the combining anti-inflammatory and immune enhancing agents can significantly improve the outcome of severe sepsis. The efficacy of this therapy seems to be dose dependent on.

Effect of recombinant human thymosin-alpha1, an immuno-modulating peptide with 28 amino acids, on the activity of cytochrome P450s.

There is an increasing application of protein/peptide drugs in the treatment of various diseases such as cancer and autoimmune diseases in clinical settings. However, data is scant on the potential for modulation of cytochrome P450s (CYPs) by these protein/peptide drugs. In this study, we examined the effects of recombinant human thymosin-alpha1 (rh-T alpha 1) on hepatic cytochrome P450 (CYP) enzyme activity in rats in vitro and in vivo. For the in vitro experiments, rh-T alpha 1 was incubated with the probe drugs and the liver microsomes from rats, while rh-T alpha 1 was administered to rats subcutaneously at 150, 300, or 600 microg/kg daily for two weeks in in vivo studies. The activities of six rat hepatic CYP enzymes, namely CYP1A2, CYP2C6, CYP2C11, CYP2D2, CYP2E1, and CYP3A1/2, were determined by a cocktail of probe drugs including phenacetin (O-deethylation), tolbutamide (4-hydrolylation), omeprazole (5-hydroxylation), dextromethorphan (O-demethylation), chlorzoxazone (6-hydroxylation), and nifedipine (N-dehydrogenation), respectively. Co-incubation of rh-T alpha(1) at the concentration of 20 and 50 micromol/l with the liver microsomes significantly inhibited CYP2E1 activity, whereas there was no significant effect on the activities of CYP1A2, CYP2C6, CYP2C11, CYP2D2, and CYP3A1/2. As to in vivo studies, treatment of rh-T alpha 1 at either dosage did not significantly alter the liver weight. However, an ex vivo study demonstrated that the activity of rat hepatic CYP2E1 was significantly increased by pretreatment of rh-T alpha 1 at the three doses for two weeks, and the activities of CYP1A2, CYP2D2, and CYP3A1/2 were also significantly increased in rats pretreated with rh-T alpha 1 at 600 microg/kg. These data indicate that rh-T alpha 1 can modulate the activities of major rat CYP isoforms, and further studies are needed to investigate its effect on human CYP activities and the potential for causing drug interactions.

Immunomodulatory therapy for chronic hepatitis B virus infection.

Hepatitis B virus (HBV) is one of the most prevalent viral pathogens of man with around 350 million chronically infected patients. It has been postulated that in persistently infected individuals the HBV-specific immune response is too weak to eliminate HBV from all infected hepatocytes, but sufficiently strong to continuously destroy HBV-infected hepatocytes and to induce chronic inflammatory liver disease. The primary aim in the treatment of chronic hepatitis B is to induce sustained disease remission and prevent serious complications like liver failure and/or hepatocellular carcinoma. The recent emergence of drug-resistant HBV mutants and post-treatment relapse as a consequence of nucleoside analogue monotherapy emphasizes that the principal goal should be to stimulate a successful immune response. In this paper we will focus on the immune response to HBV and we will review reported data on immunotherapeutic strategies like immunomodulatory drugs (cytokines and Thymic derivates) and vaccine therapies using currently available recombinant anti-HBV vaccines, lipopeptide-based T cell vaccine and newly developed genetic vaccines.

[Transcatheter hepatic arterial chemoembolization and thymosin alpha1 in postoperative treatment of hepatocellular carcinoma].

OBJECTIVE: To observe the effect of postoperative transcatheter hepatic arterial chemoembolization (TACE) and thymosin alpha(1) (T(alpha1)) treatment on recurrence of hepatocellular carcinoma (HCC). METHODS: From Jan 2000 to Dec 2002, 57 patients with HCC were randomly divided into three groups: group A (n = 18) received hepatectomy plus postoperative TACE and T(alpha1), group B (n = 23) received hepatectomy plus postoperative TACE and group C (n = 16) received hepatectomy only. The recurrence rate, the time to tumor recurrence and the median survival for the three groups were investigated. RESULTS: For group A, B and C, the 1 year recurrence rate was 83.3%, 87.0% and 87.5% (P = 0.926), respectively. The time to tumor recurrence was 7.0, 5.0 and 4.0 months (P = 0.039), respectively. The median survival was 10.0, 7.0 and 8.0 months (P = 0.002), respectively. CONCLUSION: Postoperative TACE plus Talpha(1) treatment for HCC patients does not decrease the recurrence rate but may delay its occurrence and prolong surviving time.

Thymosin alpha1 accelerates restoration of T cell-mediated neutralizing antibody response in immunocompromised hosts.

Thymosin alpha1 is a biological response modifier that has been used clinically for the treatment of chronic hepatitis B viral infection. Both immunomodulatory and immediate intracellular mechanisms have been postulated to explain the effect of thymosin alpha1 on hepatocytes infected with hepatitis B virus (HBV). Here, we established a new animal model and the related suitable conditions to access the thymosin activity by means of measuring the production of neutralizing antibody against hepatitis B surface antigen (HBsAg). We proved that chemically synthesized thymosin alpha1 restored the T cell-mediated antibody production following its suppression in mice by 5-fluorouracil (5-FU), and found that thymosin alpha1 showed activity at a low dose of 30 microg/kg. Further studies utilizing the flowcytometric analysis showed that thymosin alpha1 at this dose accelerated the replenishment and maturation of thymocytes while the expression of Smoothened (Smo) of the Hedgehog (Hh)-signaling in CD4-CD8- thymocytes, the potent negative regulator of proliferative responses, was not affected. The restoration of some of the defects in the host defense systems may facilitate elimination of infectious agents, and the present study provides a novel model to define the restoration of T cell-mediated immune responses to hepatitis B virus in vivo.

Prothymosin alpha selectively enhances estrogen receptor transcriptional activity by interacting with a repressor of estrogen receptor activity.

We find that prothymosin alpha (PTalpha) selectively enhances transcriptional activation by the estrogen receptor (ER) but not transcriptional activity of other nuclear hormone receptors. This selectivity for ER is explained by PTalpha interaction not with ER, but with a 37-kDa protein denoted REA, for repressor of estrogen receptor activity, a protein that we have previously shown binds to ER, blocking coactivator binding to ER. We isolated PTalpha, known to be a chromatin-remodeling protein associated with cell proliferation, using REA as bait in a yeast two-hybrid screen with a cDNA library from MCF-7 human breast cancer cells. PTalpha increases the magnitude of ERalpha transcriptional activity three- to fourfold. It shows lesser enhancement of ERbeta transcriptional activity and has no influence on the transcriptional activity of other nuclear hormone receptors (progesterone receptor, glucocorticoid receptor, thyroid hormone receptor, or retinoic acid receptor) or on the basal activity of ERs. In contrast, the steroid receptor coactivator SRC-1 increases transcriptional activity of all of these receptors. Cotransfection of PTalpha or SRC-1 with increasing amounts of REA, as well as competitive glutathione S-transferase pulldown and mammalian two-hybrid studies, show that REA competes with PTalpha (or SRC-1) for regulation of ER transcriptional activity and suppresses the ER stimulation by PTalpha or SRC-1, indicating that REA can function as an anticoactivator in cells. Our data support a model in which PTalpha, which does not interact with ER, selectively enhances the transcriptional activity of the ER but not that of other nuclear receptors by recruiting the repressive REA protein away from ER, thereby allowing effective coactivation of ER with SRC-1 or other coregulators. The ability of PTalpha to directly interact in vitro and in vivo with REA, a selective coregulator of the ER, thereby enabling the interaction of ER with coactivators, appears to explain its ability to selectively enhance ER transcriptional activity. These findings highlight a new role for PTalpha as a coregulator activity-modulating protein that confers receptor specificity. Proteins such as PTalpha represent an additional regulatory component that defines a novel paradigm enabling receptor-selective enhancement of transcriptional activity by coactivators.

[The effect of thymosin fractions on the development of compression edema-swelling of the brain]. / Vliianie fraktsii timozina na razvitie kompressionnogo oteka-nabukhaniia golovnogo mozga.

The search for pathogenetically drugs for the treatment and prevention of edema-swelling of the brain (ESB) is one of the urgent problems of modern biology and medicine. Immune reactions take part in the development of pathological reactions in ESB formation. The antiedemic action of drugs affecting simultaneously the processes in the nervous and immune systems was studied. Such properties are possessed by regular peptides--thymosin fractions. It was demonstrated on a model that the antiedemic effect of thymic peptides under study was due to the influence of the mediator systems: serotonin and adrenergic. The data obtained allowed the antiedemic mechanism of the effect of thymoptin to be associated with its immunostimulating effect. At the same time, the antiedemic effect of thymalin is not connected directly with the immunostimulating action of the drug.

A role of the thymus and thymosin-alpha1 in brain NGF levels and NGF receptor expression.

Using neonatal rats we investigated the role of the thymus and thymosin-alpha1 (T-alpha1) in brain NGF levels, NGF receptor (p75NGFr) expression, as well as the activity of choline acetyl-transferase, a cholinergic enzyme regulated by NGF. It is shown that early postnatal thymectomy causes a decrease in NGF in the hippocampus and cortex and p75NGFr distribution in the basal forebrain cholinergic neurons (FBCN). Intracerebral T-alpha1 injection in thymectomized animals induces a recovery, albeit not complete, of both NGF and p75NGFr. These findings indicate that thymectomy affects both the brain NGF producing and responding cells and that T-alpha1 may be one of the thymic hormones involved in the regulation of cerebral NGF synthesis.