Acidic Nuclear Protein Research Articles

Effect of prothymosin α on neuroplasticity following cerebral ischemia‑reperfusion injury.

Prothymosin α (ProT), a highly acidic nuclear protein with multiple cellular functions, has shown potential neuroprotective properties attributed to its anti‑necrotic and anti‑apoptotic activities. The present study aimed to investigate the beneficial effect of ProT on neuroplasticity after ischemia‑reperfusion injury and elucidate its underlying mechanism of action. Primary cortical neurons were either treated with ProT or overexpressing ProT by gene transfection and exposed to oxygen‑glucose deprivation for 2h invitro. Immunofluorescence staining for ProT and MAP‑2 was performed to quantify ProT protein expression and assess neuronal arborization. Mice treated with vehicle or ProT (100µg/kg) and ProT overexpression in transgenic mice received middle cerebral artery occlusion for 50min to evaluate the effect of ProT on neuroplasticity‑associated protein following ischemia‑reperfusion injury. The results demonstrated that in cultured neurons ProT significantly increased neurite lengths and the number of branches, accompanied by an upregulation mRNA level of brain‑derived neurotrophic factor. Furthermore, ProT administration improved the protein expressions of synaptosomal‑associated protein, 25kDa and postsynaptic density protein 95 after ischemic‑reperfusion injury invivo. These findings suggested that ProT can potentially induce neuroplasticity effects following ischemia‑reperfusion injury.

Anti-NF-κB peptide derived from nuclear acidic protein attenuates ovariectomy-induced osteoporosis in mice.

NF-κB is a transcription factor that is activated with aging. It plays a key role in the development of osteoporosis by promoting osteoclast differentiation and inhibiting osteoblast differentiation. In this study, we developed a small anti-NF-κB peptide called 6A-8R from a nuclear acidic protein (also known as macromolecular translocation inhibitor II, Zn2+-binding protein, or parathymosin) that inhibits transcriptional activity of NF-κB without altering its nuclear translocation and binding to DNA. Intraperitoneal injection of 6A-8R attenuated ovariectomy-induced osteoporosis in mice by inhibiting osteoclast differentiation, promoting osteoblast differentiation, and inhibiting sclerostin production by osteocytes in vivo with no apparent side effects. Conversely, in vitro, 6A-8R inhibited osteoclast differentiation by inhibiting NF-κB transcriptional activity, promoted osteoblast differentiation by promoting Smad1 phosphorylation, and inhibited sclerostin expression in osteocytes by inhibiting myocyte enhancer factors 2C and 2D. These findings suggest that 6A-8R has the potential to be an antiosteoporotic therapeutic agent with uncoupling properties.

Morin mitigates cadmium-induced testicular impairment by stimulating testosterone secretion and germ cell proliferation in mice.

Cadmium (Cd) is one of the heavy metal pollutants present in the environment due to human intervention. It is well known that Cd causes toxicological effects on various organs, including the testes. Morin hydrate is a plant-derived bioflavonoid with antioxidant, anti-inflammatory, and anti-stress properties. Thus, the question can be raised as to whether Morin has an effect on Cd-intoxication-induced testicular impairment. Therefore, the aim of this study was to investigate the role of Morin on Cd-mediated disruption of testicular activity. Mice were divided into three groups: group 1 served as thecontrol group, group 2 was given Cd (10 mg/kg) orally for 35 days, and group 3 was given Cd and Morin hydrate (100 mg/kg) for 35 days. To validate the in vivo findings, an in vitro study on testicular explants was also performed. The results of the in vivo study showed that Cd-intoxicated mice had testicular disorganization, reduced circulating testosterone levels, decreased sperm density, and elevated oxidative stress and sperm abnormality. The expression of the germ cell proliferation marker, germ cell nuclear acidic protein (GCNA), and adipocytokine visfatin were also downregulated. It was observed that Morin hydrate upregulated testicular visfatin and GCNA expression in Cd-intoxicated mice, along with improvement in circulating testosterone, testicular histology, and sperm parameters. Furthermore, the in vitro study showed that Cd-mediated downregulation of testicular visfatinand GCNA expression, along with the suppressed secretion of testosterone from testicular explants, was normalized by Morin treatment, whereas visfatin expression was not. Overall, these data indicate that environmental cadmium exposure impairs testicular activity through downregulation of visfatin and GCNA expression, and Morin might play a protective role against Cd-induced testicular toxicity.

GCNA is a histone binding protein required for spermatogonial stem cell maintenance.

Recycling and de-novo deposition of histones during DNA replication is a critical challenge faced by eukaryotic cells and is coordinated by histone chaperones. Spermatogenesis is highly regulated sophisticated process necessitating not only histone modification but loading of testis specific histone variants. Here, we show that Germ Cell Nuclear Acidic protein (GCNA), a germ cell specific protein in adult mice, can bind histones and purified GCNA exhibits histone chaperone activity. GCNA associates with the DNA replication machinery and supports progression through S-phase in murine undifferentiated spermatogonia (USGs). Whilst GCNA is dispensable for embryonic germ cell development, it is required for the maintenance of the USG pool and for long-term production of sperm. Our work describes the role of a germ cell specific histone chaperone in USGs maintenance in mice. These findings provide a mechanistic basis for the male infertility observed in patients carrying GCNA mutations.

Role of drenched barley in improving cerebral structure and function in hypercholesterolemic albino rat dam

High cholesterol diet was responsible for metabolic disease development that considers one of the public health problems. However, there is a little information about the impact of barley supplementation on hypercholesterolemia associated cerebral damage. Sixty virgin female albino rats (Rattus norvegicus) weighing 100 g body weight were used and categorized into four groups (control, barley, a hypercholesterolemic diet with/without barley). The hypercholesterolemic females ingested a high cholesterol diet (3% cholesterol) for four months before conception and throughout gestation and lactation period. Dams of the studied groups were sacrificed at the third week-postpartum. Cerebrum was removed and processed for histopathological, proliferating cell nuclear antigen (PCNA) and glial fibrillary acidic protein (GFAP) immunohistochemical investigations. Assessments of antioxidants, lipid peroxidation, neurotransmitters and interleukins levels were carried out. The present findings showed that the ingestion of drenched barley to mothers fed on a high cholesterol diet decreased lipid peroxidation, and decreased inflammatory markers coincides with increased assayed both antioxidant enzymes and neurotransmitters. These were reflected in the histological picture as well as increased proliferating cell nuclear antigen and decreased glial fibrillary acidic protein immunohistochemically. The authors concluded that drenched barley contains essential nutrients and flavonoids which increased the antioxidant defense facilitated to improve the drastic damage induced by a high cholesterol diet on cerebral neurons and restored their functional activity.

A small nuclear acidic protein (MTI-II, Zn2+-binding protein, parathymosin) attenuates TNF-α inhibition of BMP-induced osteogenesis by enhancing accessibility of the Smad4-NF-κB p65 complex to Smad binding element.

Pro-inflammatory cytokines prevent bone regeneration in vivo and activation of nuclear factor-κB (NF-κB) signaling has been proposed to lead to suppression of bone morphogenetic protein (BMP)-induced osteogenesis via direct binding of p65 to Smad4 in vitro. Application of a small nuclear acidic protein (MTI-II) and its delivered peptide, MPAID (MTI-II peptide anti-inflammatory drug) has been described to elicit therapeutic potential via strong anti-inflammatory action following the physical association of MTI-II and MPAID with p65. However, it is unclear whether MTI-II attenuates tumor necrosis factor (TNF)-α inhibition of BMP-induced osteogenesis. Herein, we found that TNF-α-mediated suppression of responses associated with BMP4-induced osteogenesis, including expression of the osteocalcin encoding gene Ocn, Smad binding element (SBE)-dependent luciferase activity, alkaline phosphatase activity, and alizarin red S staining were largely restored by MTI-II and MPAID in MC3T3-E1 cells. Mechanistically, MTI-II and MPAID did not inhibit nuclear translocation of p65 or disassociate Smad4 from p65. Further, results from chromatin immunoprecipitation (ChIP) analyses revealed that Smad4 enrichment in cells over-expressing MTI-II and treated with TNF-α was equivalent to that in cells without TNF-α treatment. Alternatively, Smad4 enrichment was considerably decreased following TNF-α treatment in control cells. Moreover, p65 enrichment in the Id-1 promoter SBE was detected only when cells over-expressing MTI-II were stimulated with TNF-α. Overall, our study concludes that MTI-II restored TNF-α-inhibited suppression of BMP-Smad-induced osteogenic differentiation by enhancing accessibility of the Smad4-p65 complex to the SBE rather than by liberating Smad4 from p65.

NKAP alters tumor immune microenvironment and promotes glioma growth via Notch1 signaling

BackgroundGlioma is one of the most aggressive malignant brain tumors which is characterized with highly infiltrative growth and poor prognosis. NKAP (NF-κB activating protein) is a widely expressed 415-amino acid nuclear protein that is overexpressed by gliomas, but its function in glioma was still unknown.MethodsCCK8 and EDU assay was used to examine the cell viability in vitro, and the xenograft models in nude mice were established to explore the roles of NAKP in vivo. The expressions of NKAP, Notch1 and SDF-1 were analyzed by immunofluorescence analysis. The expression of NKAP and Notch1 in glioma and normal human brain samples were analyzed by immunohistochemical analysis. In addition, CHIP, Gene chip, western blot, flow cytometry, immunofluorescence, ELISA and luciferase assay were used to investigate the internal connection between NKAP and Notch1.ResultsHere we showed that overexpression of NKAP in gliomas could promote tumor growth by contributing to a Notch1-dependent immune-suppressive tumor microenvironment. Downregulation of NKAP in gliomas had abrogated tumor growth and invasion in vitro and in vivo. Interestingly, compared to the control group, inhibiting NKAP set up obstacles to tumor-associated macrophage (TAM) polarization and recruitment by decreasing the secretion of SDF-1 and M-CSF. To identify the potential mechanisms involved, we performed RNA sequencing analysis and found that Notch1 appeared to positively correlate with the expression of NKAP. Furthermore, we proved that NKAP performed its function via directly binding to Notch1 promoter and trans-activating it. Notch1 inhibition could alleviate NKAP’s gliomagenesis effects.Conclusionthese observations suggest that NKAP promotes glioma growth by TAM chemoattraction through upregulation of Notch1 and this finding introduces the potential utility of NKAP inhibitors for glioma therapy.

Immunohistochemical method of simultaneous detection of neurons and astrocytes in the rat brain

This study aimed to develop a method of simultaneous immunohistochemical detection of neurons and astrocytes using peroxidase labeling with subsequent analysis by light microscopy. A pair of antigens, each of which specifically identifies either neurons or astrocytes, was chosen (as markers neuronal nuclear antigen and glial fibrillary acidic protein were used, respectively). This method not only identifies the studied cells, but it also assesses their functional state under normal and pathological conditions. The proposed staining protocol allows significant simplification and optimization to simultaneously detect two antigens and to improve the quality of the slices obtained.

PHAP1 promotes glioma cell proliferation by regulating the Akt/p27/stathmin pathway.

PHAP1 (Putative HLA‐DR‐associated protein 1), also termed acidic leucine‐rich nuclear phosphoprotein 32A (ANP32A), Phosphoprotein 32 (pp32) or protein phosphatase 2A inhibitor (I1PP2A), is a multifunctional protein aberrantly expressed in multiple types of human cancers. However, its expression pattern and clinical relevance in human glioma remain unknown. In this study, Western blotting and immunohistochemistry analysis demonstrated PHAP1 protein was highly expressed in glioma patients, especially in those with high‐grade disease. Publicly available data also revealed high levels of PHAP1 were associated with poor prognosis in glioma patients. The functional studies showed that knock‐down of PHAP1 suppressed the proliferation of glioma cells, while overexpression of PHAP1 facilitated it. The iTRAQ proteomic analysis suggested that stathmin might be a potential downstream target of PHAP1. Consistently, PHAP1 knock‐down significantly decreased the expression of stathmin, while overexpression of PHAP1 increased it. Also, the upstream negative regulator, p27, expression levels increased upon PHAP1 knock‐down and decreased when PHAP1 was overexpressed. As a result, the phosphorylated Akt (S473), an upstream regulator of p27, expression levels decreased upon silencing of PHAP1, but elevated after PHAP1 overexpression. Importantly, we demonstrate the p27 down‐regulation, stathmin up‐regulation and cell proliferation acceleration induced by PHAP1 overexpression were dependent on Akt activation. In conclusion, the above results suggest that PHAP1 expression is elevated in glioma patients, which may accelerate the proliferation of glioma cells by regulating the Akt/p27/stathmin pathway.

Identification of novel single nucleotide polymorphism at thyroid hormone responsive (THRSP) gene of native goat breeds of India

Precise knowledge about the genes causing variation within a trait will provide an opportunity for more effective marker assisted selection. Thyroid hormone responsive (THRSP) gene encodes for small acidic nuclear protein, associated with growth and lactation. Therefore, the present study was planned to detect single nucleotide variations in THRSP gene of goats. Genomic DNA was isolated from 200 animals belonging to Malabari and Attapady Black goats and PCR was done to amplify intron-1 (472bp) and exon-2 (412bp) region of THRSP gene. Single strand conformation polymorphism (SSCP) technique was used to detect single nucleotide polymorphisms (SNPs).Two unique band patterns were detected in 472bp fragment of THRSP gene. The pooled population frequencies of GG and GA diplotype were 0.88 and 0.12, respectively. The haplotype frequencies were 0.94 for G and 0.06 for a haplotype. Similar pattern of three bands were noticed in exon-2 region of THRSP gene in goats and the population was found to be monomorphic. Sequencing revealed two single nucleotide variations including a novel g.56G>T and g.306A>G in intron-1 of THRSP gene. This study indicates the existence of genetic variability in THRSP gene on goats. Hence, it could be used as a marker for selection to improve growth traits in goats.

A Small Nuclear Acidic Protein (MTI-II, Zn2+ Binding Protein, Parathymosin) That Inhibits Transcriptional Activity of NF-κB and Its Potential Application to Antiinflammatory Drugs

Nuclear factor-κB (NF-κB) is the most potent proinflammatory transactivator, and an inhibitor of NF-κB is a good antiinflammatory drug. Glucocorticoids (GCs) are the strongest and the most frequently used antiinflammatory drugs. GC-bound glucocorticoid receptor (GR) inhibits the transcriptional activity of NF-κB and thereby suppresses a broad range of inflammatory processes. Concurrently, in whole body outside the inflammation area, the GR exerts a lot of hormone action, which results in severe side effects. There is a long-awaited need for a new NF-κB inhibitor. Previously we found a small nuclear acidic protein (named MTI-II, also known as Zn2+-binding protein or parathymosin), which worked as a coactivator of GR. Here we showed that overexpression of MTI-II inhibited a transcriptional activity of NF-κB independently of GCs and the GR. Vise versa, RNA interference suppression of inherent MTI-II enhanced the transcriptional activity of NF-κB. An immunoprecipitation analysis showed that MTI-II precipitated NF-κB after the stimulation of TNFα. Deletion mutants of MTI-II showed that central acidic region is essential for the inhibition of the transcriptional activity of NF-κB. These results suggest that MTI-II would be an inherent inhibitor that interacts with NF-κB. Next, we constructed MTI-II-based antiinflammatory drugs (three fusion proteins of MTI-II with a protein transduction domain and a fusion peptide of the central acidic region with protein transduction domain). These drugs had significant antiinflammatory effects on acute inflammation models and on animal models of human chronic inflammation diseases without an increase of the blood glucose level and repeated-dose toxicity. The MTI-II-based antiinflammatory drug will be a good alternative of GCs.

Abstract 138: Inhibition of Stress-inducible Genes That Distinguish Pathological Cardiac Hypertrophy via Targeting Acidic Nuclear Protein 32e

Cardiac hypertrophy is a manifestation of an increase in the workload imposed on the heart. The cause, duration, and extent of the workload dictate the physiological vs. pathological nature of the hypertrophy and its likelihood to transition into cardiac failure. Our goal is to identify differences between these 2 forms of hypertrophy by examining the binding patterns of key basic transcription factors and regulators in a genome-wide fashion. Our data show that a pause-release mechanism of RNA polymerase II (pol II) bound to the transcriptional start site (TSS) induces housekeeping/essential genes (~ 63% of expressed genes), in a synchronous and incremental fashion that is proportional to the increase in myocyte size and does not require de novo pol II binding. This mechanism is responsible for the increase in cell size and mass that constitute hypertrophy in both physiological and pathological forms. Superimposed on this is a second and critical group of genes (~3.5%) that are stress-induced in the pathological form of hypertrophy but are minimally, if at all, expressed in the postnatal and adult heart (e.g. Acta1, Ankrd1, Xirp2, Nppa, Col1a1 ..etc). In contrast to the housekeeping genes, these genes require de novo pol II recruitment and exhibit a robust increase in expression. To further identify the transcriptional mechanisms that distinguish these sets of genes, we performed chromatin immunoprecipitation-deep sequencing (ChIP-Seq) analysis for cyclin-dependent kinase 9 (Cdk9) and histone H2A.z. The results reveal an increase in Cdk9 at the TSS of paused genes vs. an increase at TSS and throughout the gene body of inducible genes. In contrast, H2A.z levels remained constant. However, we found that Acidic Nuclear Protein 32e (Anp32e), a nuclear protein phosphatase 2A (PP2A) inhibitor, interacted with H2A.z and regulated phosphorylation of Cdk9. Interestingly, knockdown of Anp32e during pressure overload hypertrophy resulted in 70-90% inhibition of stress-inducible genes, but only an incremental inhibition of the increase in cardiac size. Thus, we propose that targeting Anp32e may partially revert pathological hypertrophy to a more physiological form via specifically inhibiting the stress-induced genes while preserving the increase in cardiac mass.

Over‐expression of prothymosin‐α antagonizes TGFβ signalling to promote the development of emphysema

Emphysema, a major consequence of chronic obstructive pulmonary disease (COPD), is characterized by the permanent airflow restriction resulting from enlargement of alveolar airspace and loss of lung elasticity. Transforming growth factor-β (TGFβ) signalling regulates the balance of matrix metalloproteinase (MMP)/tissue inhibitor of matrix metalloproteinase (TIMP) to control matrix homeostasis. Patients with COPD have dysregulated TGFβ signalling and reduced histone deacetylase (HDAC) activity through epigenetic up-regulation of histone acetylation in the promoters of pro-inflammatory genes. However, the potential link between decreased HDAC activity and dysregulated TGFβ signalling in emphysema pathogenesis remains to be determined. Prothymosin α (ProT), a highly conserved acidic nuclear protein, plays a role in the acetylation of histone and non-histone proteins. The aim of this study was to test the hypothesis that ProT inhibits TGFβ-Smad signalling through Smad7, thereby contributing to emphysema pathogenesis. We show that ProT enhances Smad7 acetylation by decreasing its association with HDAC and thereby down-regulates TGFβ-Smad signalling. ProT caused an imbalance between MMP and TIMP through acetylated Smad7 in favour of MMP expression. In addition to interfering with R-Smad activation and targeting receptors for degradation in the cytoplasm, acetylated Smad7 potentiated by ProT competitively antagonized binding of the pSmad2/3-Smad4 complex to the TIMP-3 promoter, resulting in reduced TIMP-3 expression. These effects were detected in ProT-over-expressing cells, lungs of ProT transgenic mice displaying an emphysema phenotype and in emphysema patients. Importantly, increased Smad7 and reduced TIMP-3 were found in the lungs of emphysema patients and mice with cigarette smoke extract (CSE)-induced emphysema. Such effects could be abrogated by silencing endogenous ProT expression. Collectively, our results uncover acetylated Smad7 regulated by ProT as an important determinant in dysregulated TGFβ signalling that contributes to emphysema pathogenesis.

Abstract 19657: Histone Variant H2a.z And Cdk9 Differentially Regulate Transcriptional Rates During Cardiac Hypertrophy

Genome-wide modifications in basic transcriptional activity underlie cardiac development and disease. We have previously reported that transcriptional regulation by RNA polymerase II (pol II) distinguishes different functional gene categories. In particular, transcription of constitutive, housekeeping, genes is regulated by a pause/release mechanism vs. de novo recruitment of pol II to cardiac-specific and inducible genes during cardiac hypertrophy in mice. Our objective is to identify the epigenetics and nuclear proteins that distinguish these transcriptional patterns. Using chromatin immunoprecipitation-deep sequencing (ChIP-Seq) we identified relatively high levels of H2A.z at the transcriptional start site of all housekeeping and inducible genes that exhibited only minimal or no changes in the heart before or after induction of pressure overload. In contrast, however, all cardiac-specific genes were consistently devoid of H2A.z. We also identified the specific interaction between H2A.z and acidic nuclear protein 32e (ANP32e), which inhibits the dephosphorylation and deactivation of cyclin-dependent kinase 9 (Cdk9) by protein phosphatase 2A (PP2A) and enhances its recruitment to chromatin. Accordingly, cardiac-specific and inducible genes diverge with regards to their regulation by Cdk9, where pressure overload induces a strict decrease vs. increase of Cdk9, respectively, at the promoter and gene body regions of these gene categories. Paradoxically, the reduction in Cdk9 in the former genes is accompanied by an increase in pol II levels, with a net result of little or no change in transcriptional rates. On the other hand, inducible genes are characterized by high levels of de novo recruitment of both pol II and Cdk9, with a sharp increase in transcriptional rates, which was specifically and completely inhibited by knockdown of Cdk9, or its inhibitors 5, 6- dichloro-1-β-D-ribofuranosyl-1H-benzimidazole or inhibitor II. Thus, the differential recruitment of H2A.z and Cdk9 determines the elongational rate of pol II that discriminates between the transcriptional rates of pressure overload-induced v. constitutively-expressed cardiac-specific genes.

RETRACTED: A purine antimetabolite attenuates toll-like receptor-2, -4, and subarachnoid hemorrhage-induced brain apoptosis

BackgroundUpregulation of high-level toll-like receptors (TLRs) is observed in the serum of animals following experimental subarachnoid hemorrhage (SAH) and is highly related to SAH-induced early brain injury (EBI). The present study was of interest to examine the effect of 6-mercaptopurine (6-MP) on alternation of TLR-2, -3, and -4 in this model. MethodsA rodent SAH model was used. Administration with 6-MP (0.5/1/2 mg/kg/d) was initiated 1 h after the induction of SAH via an osmotic minipump. Cerebral cortex was harvested to measure TLRs messenger RNA and protein (reverse transcription polymerase chain reaction [rt-PCR] and Western blot). Cerebral cortex was harvested for activated caspases (rt-PCR) measurement. ResultsCellular evaluation revealed increased neuronal nuclei(+) neurons with vacuolated nuclear and glial fibrillary acidic protein(+) astrocytes in the SAH group, but absent in the 6-MP treatment and healthy controls. The TLR-3 levels were not significantly increased in animals subject to SAH, compared with the controls (no SAH). The levels of TLR-2 and -4 in the SAH only and SAH plus vehicle groups were significantly elevated (P < 0.01), and treatment with 6-MP reduced TLR-2, -3 (at 2 mg/kg), and -4 (dose-dependently) protein expression following SAH. Likewise, the TLR-4 messenger RNA levels were also significantly reduced in the 6-MP (at 1 mg/kg and 2 mg/kg) groups. Cleaved caspase-3 and caspase-9a were reduced at 2-mg/kg 6-MP treatment group. ConclusionsThese results show that 6-MP attenuates the expression of TLR-2, -4, especially TLR-4, which play an antiapoptotic effect on SAH-induced EBI. This finding supported that through modulating TLRs, 6-MP can attenuate SAH-induced EBI. Those results offer credit to the neuroprotective effect of 6-MP.

Cloning, soluble expression, and purification of the RNA polymerase II subunit RPB5 from Saccharomyces cerevisiae

We report the molecular cloning, expression, and single-step homogeneous purification of RNA polymerase II subunit RPB5 from Saccharomyces cerevisiae. RPB5 is a 210 amino acid nuclear protein that functions as the fifth largest subunit of polymerase II and plays a central role in transcription. The gene that codes for RPB5 was generated by amplification by polymerase chain reaction. It was then inserted in the expression vector pET28a(+) under the transcriptional control of the bacteriophage T7 promoter and lac operator. BL21(DE3) Escherichia coli strain transformed with the rpb5 expression vector pET28a(+)-rpb5 accumulates large amounts of a soluble protein of about 30 kDa (25 kDa plus 5 kDa double His6-Tag at N and C-terminal). The protein was purified to homogeneity using immobilized metal affinity chromatography. RPB5 recombinant protein was further confirmed by immunoblotting with anti-His antibody. In this study, the expression and purification procedures have provided a simple and efficient method to obtain pure RPB5 in large quantities. This will provide an opportunity to study the role of S. cerevisiae RPB5 in gene expression and transcription regulation. Furthermore, it can provide additional knowledge of the interaction partners of RPB5 during various steps of transcription and gene expression.

Neonatal maternal separation up-regulates protein signalling for cell survival in rat hypothalamus

We have previously reported that in response to early life stress, such as maternal hyperthyroidism and maternal separation (MS), the rat hypothalamic vasopressinergic system becomes up-regulated, showing enlarged nuclear volume and cell number, with stress hyperresponsivity and high anxiety during adulthood. The detailed signaling pathways involving cell death/survival, modified by adverse experiences in this developmental window remains unknown. Here, we report the effects of MS on cellular density and time-dependent fluctuations of the expression of pro- and anti-apoptotic factors during the development of the hypothalamus. Neonatal male rats were exposed to 3 h-daily MS from postnatal days 2 to 15 (PND 2–15). Cellular density was assessed in the hypothalamus at PND 21 using methylene blue staining, and neuronal nuclear specific protein and glial fibrillary acidic protein immunostaining at PND 36. Expression of factors related to apoptosis and cell survival in the hypothalamus was examined at PND 1, 3, 6, 9, 12, 15, 20 and 43 by Western blot. Rats subjected to MS exhibited greater cell-density and increased neuronal density in all hypothalamic regions assessed. The time course of protein expression in the postnatal brain showed: (1) decreased expression of active caspase 3; (2) increased Bcl-2/Bax ratio; (3) increased activation of ERK1/2, Akt and inactivation of Bad; PND 15 and PND 20 were the most prominent time-points. These data indicate that MS can induce hypothalamic structural reorganization by promoting survival, suppressing cell death pathways, increasing cellular density which may alter the contribution of these modified regions to homeostasis.

Prothymosin alpha protects cardiomyocytes against ischemia-induced apoptosis via preservation of Akt activation

The human prothymosin alpha (PTα) gene encodes a 12.5kDa highly acidic nuclear protein that is widely expressed in mammalian tissues including the heart and importantly, is detectable also in blood serum. During apoptosis or necrosis, PTα changes its nuclear localization and is able to exert an important cytoprotective effect. Since the role of PTα in the heart has never been evaluated, the aim of the present study was to investigate the effects of PTα on cardiomyocytes during ischemic injury. Our data show that seven after myocardial infarction (MI), PTα expression levels are significantly increased both in blood serum and in cardiac tissue, and notably we observe that PTα translocates from the nuclei to cytoplasm and plasma membrane of cardiomyocytes following MI. Furthermore, in vitro experiments in cardiomyocytes, confirm that after 6h of simulated ischemia (SI), PTα protein levels are upregulated compared to normoxic cells. Importantly, treatment of cardiomyocytes with a recombinant PTα (rPTα), during SI results in a significant decrease in the apoptotic response and in a robust increase in cell survival. Moreover, these effects are accompanied to a significant preservation of the activated levels of the anti-apoptotic serine-threonine kinase Akt. Consistent with our in vitro observation, rPTα-treated MI mice exhibit a strong reduction in infarct size at 24h, compared to the MI control group and at the molecular level, PTα treatment induces activation of Akt. The present study provides for the first time the demonstration that PTα offers cardioprotection against ischemic injury by an Akt-dependent mechanism.

Deficiency in Cold-Inducible RNA-Binding Protein (CIRP) Improves Cutaneous Wound Healing

Wound healing is a dynamic and complex process involving hemostasis, inflammation, repair, and remodeling. Numerous enzymes and proteins are required to work in a coordinated manner during the healing process. Identifying a new mediator could advance the understanding and control of wound healing, leading to the development of specific therapeutic strategies. CIRP is a 172-amino acid nuclear protein that functions as an RNA chaperon to facilitate translation and modulate gene expression during mild hypothermic conditions.

Aging- and injury-related differential apoptotic response in the dentate gyrus of the hippocampus in rats following brain trauma

The elderly are among the most vulnerable to traumatic brain injury (TBI) with poor functional outcomes and impaired cognitive recovery. Of the pathological changes that occur following TBI, apoptosis is an important contributor to the secondary insults and subsequent morbidity associated with TBI. The current study investigated age-related differences in the apoptotic response to injury, which may represent a mechanistic underpinning of the heightened vulnerability of the aged brain to TBI. This study compared the degree of TBI-induced apoptotic response and changes of several apoptosis-related proteins in the hippocampal dentate gyrus (DG) of juvenile and aged animals following injury. Juvenile (p28) and aged rats (24 months) were subjected to a moderate fluid percussive injury or sham injury and sacrificed at 2 days post-injury. One group of rats in both ages was sacrificed and brain sections were processed for TUNEL and immunofluorescent labeling to assess the level of apoptosis and to identify cell types which undergo apoptosis. Another group of animals was subjected to proteomic analysis, whereby proteins from the ipsilateral DG were extracted and subjected to 2D-gel electrophoresis and mass spectrometry analysis. Histological studies revealed age- and injury-related differences in the number of TUNEL-labeled cells in the DG. In sham animals, juveniles displayed a higher number of TUNEL+ apoptotic cells located primarily in the subgranular zone of the DG as compared to the aged brain. These apoptotic cells expressed the early neuronal marker PSA-NCAM, suggestive of newly generated immature neurons. In contrast, aged rats had a significantly higher number of TUNEL+ cells following TBI than injured juveniles, which were NeuN-positive mature neurons located predominantly in the granule cell layer. Fluorescent triple labeling revealed that microglial cells were closely associated to the apoptotic cells. In concert with these cellular changes, proteomic studies revealed both age-associated and injury-induced changes in the expression levels of three apoptotic-related proteins: hippocalcin, leucine-rich acidic nuclear protein and heat shock protein 27. Taken together, this study revealed distinct apoptotic responses following TBI in the juvenile and aged brain which may contribute to the differential cognitive recovery observed.