Lymphoid priming in human bone marrow begins before expression of CD10 with upregulation of L-selectin.

Expression of the cell-surface antigen CD10 has long been used to define the lymphoid commitment of human cells. Here we report a unique lymphoid-primed population in human bone marrow that was generated from hematopoietic stem cells (HSCs) before onset of the expression of CD10 and commitment to the B cell lineage. We identified this subset by high expression of the homing molecule L-selectin (CD62L). CD10(-)CD62L(hi) progenitors had full lymphoid and monocytic potential but lacked erythroid potential. Gene-expression profiling placed the CD10(-)CD62L(hi) population at an intermediate stage of differentiation between HSCs and lineage-negative (Lin(-)) CD34(+)CD10(+) progenitors. CD62L was expressed on immature thymocytes, and its ligands were expressed at the cortico-medullary junction of the thymus, which suggested a possible role for this molecule in homing to the thymus. Our studies identify the earliest stage of lymphoid priming in human bone marrow.

Comparative expression profile of CD10 and cyclin D1 in cutaneous histiocytofibroma and dermatofibrosarcoma.

Dermatofibrosarcoma protuberans (DFSP) and histiocytofibroma (HF) are two rare fibrohistiocytic tumors, with some overlapping pathologic features. Immunohistochemistry is very useful in these cases. CD34 is a commonly used marker. However, the increasing cases of CD34 negative DFSP make it pressing to test other immunohistochemical markers that could help in the differential diagnosis. DFSP is known to harbor COL1A1-PDGFB rearrangement. Tumors in the differential diagnosis of DFSP usually lack this molecular signature. Recent studies suggested the interaction of PDGFB and PDGF receptor b with various signaling pathways, including the Akt-mTOR pathway. Cyclin D1, one of the oncoproteins activated in this pathway, may represent a promising useful biomarker in the differential diagnosis. On the other hand, CD10 expression in specialized mesenchymal skin cells, and especially in fibrohistiocytic skin tumors has been reported, which raises the interest of using this biomarker in HF and DFSP. In this study, we aimed to compare the expression of CD10 and cyclin D1 in 15 cases of DFSP and 15 cases of HF and discuss their potential contribution in the differential diagnosis.

Maternal Overweight Downregulates MME (Neprilysin) in Feto-Placental Endothelial Cells and in Cord Blood.

Maternal overweight in pregnancy alters the metabolic environment and generates chronic low-grade inflammation. This affects fetal development and programs the offspring's health for developing cardiovascular and metabolic disease later in life. MME (membrane-metalloendopeptidase, neprilysin) cleaves various peptides regulating vascular tone. Endothelial cells express membrane-bound and soluble MME. In adults, the metabolic environment of overweight and obesity upregulates endothelial and circulating MME. We here hypothesized that maternal overweight increases MME in the feto-placental endothelium. We used primary feto-placental endothelial cells (fpEC) isolated from placentas after normal vs. overweight pregnancies and determined MME mRNA, protein, and release. Additionally, soluble cord blood MME was analyzed. The effect of oxygen and tumor necrosis factor α (TNFα) on MME protein in fpEC was investigated in vitro. Maternal overweight reduced MME mRNA (-39.9%, p < 0.05), protein (-42.5%, p = 0.02), and MME release from fpEC (-64.7%, p = 0.02). Both cellular and released MME protein negatively correlated with maternal pre-pregnancy BMI. Similarly, cord blood MME was negatively associated with pre-pregnancy BMI (r = -0.42, p = 0.02). However, hypoxia and TNFα, potential negative regulators of MME expression, did not affect MME protein. Reduction of MME protein in fpEC and in cord blood may alter the balance of vasoactive peptides. Our study highlights the fetal susceptibility to maternal metabolism and inflammatory state.

Mature CD10+ and immature CD10- neutrophils present in G-CSF-treated donors display opposite effects on T cells.

The identification of discrete neutrophil populations, as well as the characterization of their immunoregulatory properties, is an emerging topic under extensive investigation. In such regard, the presence of circulating CD66b+ neutrophil populations, exerting either immunosuppressive or proinflammatory functions, has been described in several acute and chronic inflammatory conditions. However, due to the lack of specific markers, the precise phenotype and maturation status of these neutrophil populations remain unclear. Herein, we report that CD10, also known as common acute lymphoblastic leukemia antigen, neutral endopeptidase, or enkephalinase, can be used as a marker that, within heterogeneous populations of circulating CD66b+ neutrophils present in inflammatory conditions, clearly distinguishes the mature from the immature ones. Accordingly, we observed that the previously described immunosuppressive neutrophil population that appears in the circulation of granulocyte colony-stimulating factor (G-CSF)-treated donors (GDs) consists of mature CD66b+CD10+ neutrophils displaying an activated phenotype. These neutrophils inhibit proliferation and interferon γ (IFNγ) production by T cells via a CD18-mediated contact-dependent arginase 1 release. By contrast, we found that immature CD66b+CD10- neutrophils, also present in GDs, display an immature morphology, promote T-cell survival, and enhance proliferation and IFNγ production by T cells. Altogether, our findings uncover that in GDs, circulating mature and immature neutrophils, distinguished by their differential CD10 expression, exert opposite immunoregulatory properties. Therefore, CD10 might be used as a phenotypic marker discriminating mature neutrophils from immature neutrophil populations present in patients with acute or chronic inflammatory conditions, as well as facilitating their isolation, to better define their specific immunoregulatory properties.

Primary cutaneous vs secondary cutaneous follicular lymphomas: A comparative study focused on BCL2, CD10, and t(14;18) expression.

BACKGROUND: Primary cutaneous follicular center-cell lymphoma (PCFCL) is one of the most common types of cutaneous B-cell lymphoma. Differences in immunohistochemical expression of BCL2 and CD10 antigens along with the presence of t(14:18) translocation in neoplastic cells have been postulated as relevant clues in differentiating PCFCL from cutaneous lesions secondary to a systemic follicular lymphoma (SCFL). The aim of this study is to evaluate the significance and usefulness of these parameters in a large series of patients. METHODS: Patients with PCFCL and SCFL diagnosed at three university hospitals in Barcelona, from 2000 to 2015 were reviewed. Clinical, histopathological, immunophenotypical, genetic, and outcome parameters were analyzed. RESULTS: Eighty-one cases (59 PCFCL and 22 SCFL) were included. There were no significant differences between PCFCL and SCFL cases regarding clinical presentation, site of involvement, or predominant type of skin lesions. Most patients in both groups showed positivity for BCL2 and CD10, but strong expression of BCL2 and CD10 was associated with SCFL cases. Although more frequent in SCFL, a small proportion of PCFCL cases also showed the t(14:18) on FISH analysis. CONCLUSION: The intensity of BCL2 expression was found to be the single most valuable clue in differentiating PCFCL from SCFL cases on histopathological grounds.

High expression of CD10 in anaplastic thyroid carcinomas.

AIMS: CD10 is an endopeptidase that degrades various bioactive peptides in the extracellular matrix. In addition to enzymatic degradation, it affects multiple intracellular signal transduction pathways. CD10 expression has been extensively studied in human epithelial cancers of numerous organs and sites. However, its presence in thyroid carcinomas, especially in anaplastic thyroid carcinoma (ATC), has not been fully determined. An actual CD10 expression in thyroid lesions including a large series of ATC was evaluated. METHODS AND RESULTS: We examined CD10 by immunohistochemistry (IHC) in 152 thyroid lesions: nine adenomatous goitres (AGs) and 143 tumours, including 47 anaplastic carcinomas. IHC showed diffuse and strong positivity for CD10 in the epithelial components of almost all ATCs. However, epithelia with squamous metaplasia and oncocytic change from AGs, follicular adenomas and differentiated carcinomas had focal CD10 reactivity. Some papillary thyroid carcinomas (PTCs), along with the PTC components of some ATCs, showed CD10 positivity in fibroblast-like stromal cells and fibrous material. CONCLUSION: Our results imply that the CD10 expression pattern depended on the histotypes of thyroid lesions. When possible metastatic tumours and non-epithelial tumours are excluded, high CD10 expression may be useful in determining whether a primary thyroid carcinoma includes an anaplastic component.

CD10 expression pattern in prostatic adenocarcinoma: Elucidation of differences between Gleason's grades.

CD10, a transmembrane endopeptidase, has been shown to be lost as an early event in prostate cancer. We aimed at evaluating the pattern of expression of CD10 in various Gleason's grades of prostatic adenocarcinoma in comparison with nodular hyperplasia of prostate. This retrospective study included 30 cases of nodular hyperplasia and 30 of prostatic adenocarcinoma of various Gleason's grades. Immunohistochemical staining for CD10 was performed on all cases and positivity evaluated as percentage of cells as well as location (membranous or cytoplasmic or both). Of prostatic adenocarcinomas, grade 3 was seen in 10 foci, grade 4 in 28 and grade 5 in 22 foci. CD10 positivity in carcinoma was lower than in nodular hyperplasia, with the lowest positivity in grade 5. The pattern of expression of CD10 also changed from membranous in grade 3 to cytoplasmic in grade 5. Loss of CD10 expression appears to be associated with increasing tumour grade in carcinoma prostate and this can potentially be useful in stratification of such patients.

Aberrant expression of CD10 and BCL6 in mantle cell lymphoma.

AIMS: Mantle cell lymphoma (MCL) is characterized by distinctive histological and molecular features. Aberrant expression of BCL6 and CD10 has been reported occasionally, but the biological features of such cases are largely unknown. This study aimed to define the epidemiological, histological and cytogenetic characteristics of BCL6 and CD10-positive MCLs, also investigating possible biological features. METHODS AND RESULTS: A total of 165 cases of cyclin D1 and t(11;14)(q13;q34)-positive MCLs were studied for CD10 and BCL6 immunohistochemical expression, which was documented in 26 of 165 (15.8%) cases (BCL6 17 of 165; CD10 11 of 165; BCL6 and CD10 co-expression two of 165). CD10-positivity was significantly more frequent in females (63.3%; P < 0.01). Either expression correlated significantly with higher mean proliferation index and higher prevalence of MUM1 positivity (P < 0.05). Fluorescence in-situ hybridization (FISH) for BCL6 (3q27) gene derangements was performed on the BCL6- and CD10-positive cases and 98 matched controls: amplifications were documented more frequently in BCL6-positive than -negative cases (50.0% versus 19.4% of cases) (P < 0.05). The mutational status of the variable immunoglobulin heavy chain genes (IGVH) was investigated by Sanger sequencing: five of the six successfully tested cases (83.3%) showed no somatic hypermutations. CONCLUSIONS: Aberrant CD10 and BCL6 expression defines a subset of MCLs with higher mean Ki-67 index and higher prevalence of MUM1 expression. BCL6 protein positivity correlates with cytogenetic aberrations involving the BCL6 gene. Although examined successfully in few cases, the high prevalence of unmutated IGVH genes also points at a pregerminal cell origin for these phenotypically aberrant cases.

Reduction and fragmentation of elastic fibers in the skin of obese mice is associated with altered mRNA expression levels of fibrillin-1 and neprilysin.

AIM OF THE STUDY: Our previous research suggested that obesity induces structural fragility in the skin. Elastic fibers impart strength and elasticity. In this study, we determined whether elastic fibers decrease in the skin of obese mice. MATERIALS AND METHODS: To confirm alterations in elastic fiber content due to obesity, we used spontaneously obese model mice (TSOD) and control mice (TSNO). Furthermore, to evaluate the elastin structure and gene expression dependent on the severity of obesity, an obesity-enhanced mouse model was developed by feeding a high fat diet to TSOD (TSOD-HF). Back skin samples were stained with hematoxylin and eosin and Elastica van Gieson for microscopic examination, and the samples were stained for immunohistochemical analysis of neprilysin. Gene expression levels were determined using a real-time PCR system. RESULTS: The abundance of elastic fibers beneath the epidermis was remarkably reduced and fragmented in TSOD as compared with TSNO. Fibrillin-1 mRNA levels in TSOD were significantly suppressed compared with those in TSNO, whereas neprilysin mRNA levels and immunohistochemical expression in TSOD were significantly increased, as compared with those in TSNO. The reduction of elastic fibers was enhanced and the expression levels of elastic fiber formed factors were significantly suppressed in TSOD-HF, as compared with those in the TSOD. CONCLUSIONS: The abundance of elastic fibers was reduced and fragmented in obesity, suggesting that the reduction in elastic fibers is initially caused by increased neprilysin and decreased fibrillin-1 expression, which may inhibit formation and stabilization of elastic fibers, resulting in skin fragility in obesity.

CD10 down expression in follicular lymphoma correlates with gastrointestinal lesion involving the stomach and large intestine.

Follicular lymphoma (FL) shows co-expression of B-cell lymphoma 2 (BCL2) and CD10, whereas downexpression of CD10 is occasionally experienced in gastrointestinal (GI) FL with unknown significance. Gastrointestinal FL is a rare variant of FL, and its similarity with mucosa-associated lymphoid tissue lymphoma was reported. We investigated the clinicopathological and genetic features of CD10 downexpressed (CD10down ) GI-FL. The diagnosis of CD10down FL was carried out with a combination of pathological and molecular analyses. The incidence of CD10down GI-FL was shown in 35/172 (20.3%) cases, which was more frequent than nodal FL (3.5%, P < 0.001). The difference was additionally significant between GI-FL and nodal FL when the analysis was confined to primary GI-FL (55.2% vs 3.5%, P < 0.001). Compared to CD10+ GI-FL, CD10down GI-FL significantly involved the stomach or large intestine (P = 0.015), and additionally showed the downexpression of BCL6 (P < 0.001). The follicular dendritic cell meshwork often showed a duodenal pattern in the CD10down group (P = 0.12). Furthermore, a lymphoepithelial lesion was observed in 5/12 (40%) gastric FL cases, which indicated caution in the differentiation of mucosa-associated lymphoid tissue lymphoma. Molecular analyses were undertaken in seven cases of CD10down GI-FL, and an identical clone was found between CD10down follicles and CD10+ BCL2+ neoplastic follicles. In the diagnosis of cases with CD10down BCL2+ follicles, careful examination with molecular studies should be carried out.

Green tea reduces body fat via upregulation of neprilysin.

BACKGROUND/OBJECTIVE: Consumption of green tea has become increasingly popular, particularly because of claimed reduction in body weight. We recently reported that animals with pharmacological inhibition (by candoxatril) or genetic absence of the endopeptidase neprilysin (NEP) develop an obese phenotype. We now investigated the effect of green tea extract (in drinking water) on body weight and body composition and the mediating role of NEP. SUBJECTS/METHODS: To elucidate the role of NEP in mediating the beneficial effects of green tea extract, 'Berlin fat mice' or NEP-deficient mice and their age- and gender-matched wild-type controls received the extract in two different doses (300 or 600 mg kg-1 body weight per day) in the drinking water. RESULTS: In 'Berlin fat mice', 51 days of green tea treatment did not only prevent fat accumulation (control: day 0: 30.5% fat, day 51: 33.1%; NS) but also reduced significant body fat (green tea: day 0: 27.8%, day 51: 20.9%, P<0.01) and body weight below the initial levels. Green tea reduced food intake. This was paralleled by a selective increase in peripheral (in kidney 17%, in intestine 92%), but not central NEP expression and activity, leading to downregulation of orexigens (like galanin and neuropeptide Y (NPY)) known to be physiological substrates of NEP. Consequently, in NEP-knockout mice, green tea extract failed to reduce body fat/weight. CONCLUSIONS: Our data generate experimental proof for the assumed effects of green tea on body weight and the key role for NEP in such process, and thus open a new avenue for the treatment of obesity.

Protection against vascular leak in neprilysin transgenic mice with complex overexpression pattern.

Neprilysin (NEP) is a cell surface metallopeptidase found in many tissues. Based mostly on pharmacological manipulations, NEP has been thought to protect blood vessels from plasma extravasation. We have suggested that NEP may protect against pulmonary vascular injury. However, these prior studies did not utilize mice which overexpress NEP. The aims of the present investigation were to develop and characterize doubly transgenic (DT) mice that overexpress NEP universally and conditionally, and to investigate the protective effect that overexpressed NEP may have against plasma extravasation in the vasculature. The duodenum, which is often used to assess vascular permeability, and in which the NEP protein was overexpressed in our DT mice two-fold, was selected as our experimental preparation. We found that substance P-induced plasma extravasation was decreased substantially (3.5-fold) in the duodenums of our doxycycline-treated DT mice, giving independent evidence of NEP's protective effects against plasma extravasation. Transgenic lung NEP protein was not stably expressed in the DT mice, so we were not able to test the effect of NEP overexpression in the lung. Although initially overexpressed nearly nine-fold at that site, pulmonary NEP protein overexpression eventually dissipated. Surprisingly, at a time when there was no lung transgenic NEP protein overexpression, lung NEP mRNA expression was still increased 23-fold, indicating that the expression defect probably is not transcriptional. These studies help to characterize our complex transgenic model of NEP overexpression and further demonstrate NEP's protective effects against plasma extravasation.

Cutaneous PEComas Express CD10: Implications for the Classification of PEComas and the Differential Diagnosis With Metastatic Renal Cell Carcinoma.

Cutaneous perivascular epithelioid cell tumors (PEComas) are peculiar, rare mesenchymal tumors of uncertain lineage. They show a characteristic epithelioid morphology, and they are usually composed of monomorphous clear-to-granular appearing perivascular cells. One of the main differential diagnoses with PEComas is a cutaneous metastasis from renal cell carcinoma (RCC). CD10 has been emphasized to be a crucial marker in the diagnosis of metastasis from RCC. Although visceral PEComas have been studied for CD10 expression, primary cutaneous PEComas have not. Although it could be assumed a priori that cutaneous PEComas would stain as their visceral counterpart, there is increasing evidence that cutaneous PEComas could actually be unrelated to PEComas from other organs. In this report, the author's studied three primary cutaneous PEComas, and included CD10 in our immunohistochemical studies. All three PEComas expressed the marker. They conclude that a CD10 clear-cell dermal tumor is not necessarily equivalent to a metastasis from RCC and that additional stains should be added to rule out PEComa, even if the biopsy or the panel of antibodies is limited.

B-cell lymphomas with concurrent MYC and BCL2 abnormalities other than translocations behave similarly to MYC/BCL2 double-hit lymphomas.

Large B-cell lymphomas with IGH@BCL2 and MYC rearrangement, known as double-hit lymphoma (DHL), are clinically aggressive neoplasms with a poor prognosis. Some large B-cell lymphomas have concurrent abnormalities of MYC and BCL2 other than coexistent translocations. Little is known about patients with these lymphomas designated here as atypical DHL. We studied 40 patients of atypical DHL including 21 men and 19 women, with a median age of 60 years. Nine (23%) patients had a history of B-cell non-Hodgkin lymphoma. There were 30 diffuse large B-cell lymphoma (DLBCL), 7 B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma, and 3 DLBCL with coexistent follicular lymphoma. CD10, BCL2, and MYC were expressed in 28/39 (72%), 33/35 (94%), and 14/20 (70%) cases, respectively. Patients were treated with standard (n=14) or more aggressive chemotherapy regimens (n=17). We compared the atypical DHL group with 76 patients with DHLand 35 patients with DLBCL lacking MYC and BCL2 abnormalities. The clinicopathologic features and therapies were similar between patients with atypical and typical DHL. The overall survival of patients with atypical double-hit lymphoma was similar to that of patients with double-hit lymphoma (P=0.47) and significantly worse than that of patients with DLBCL with normal MYC and BCL2 (P=0.02). There were some minor differences. Cases of atypical double-hit lymphoma more often have DLBCL morphology (P<0.01), less frequently expressed CD10 (P<0.01), and patients less often had an elevated serum lactate dehydrogenase level (P=0.01). In aggregate, these results support expanding the category of MYC/BCL2 DHL to include large B-cell lymphomas with coexistent MYC and BCL2 abnormalities other than concurrent translocations.

Herpes simplex virus type 1 infection in neurons leads to production and nuclear localization of APP intracellular domain (AICD): implications for Alzheimer's disease pathogenesis.

Several data indicate that neuronal infection with herpes simplex virus type 1 (HSV-1) causes biochemical alterations reminiscent of Alzheimer's disease (AD) phenotype. They include accumulation of amyloid-ß (Aß), which originates from the cleavage of amyloid precursor protein (APP), and hyperphosphorylation of tau protein, which leads to neurofibrillary tangle deposition. HSV-1 infection triggers APP processing and drives the production of several fragments including APP intracellular domain (AICD) that exerts transactivating properties. Herein, we analyzed the production and intracellular localization of AICD following HSV-1 infection in neurons. We also checked whether AICD induced the transcription of two target genes, neprilysin (nep) and glycogen synthase kinase 3ß (gsk3ß), whose products play a role in Aß clearance and tau phosphorylation, respectively. Our data indicate that HSV-1 led to the accumulation and nuclear translocation of AICD in neurons. Moreover, results from chromatin immunoprecipitation assay showed that AICD binds the promoter region of both nep and gsk3ß. Time course analysis of NEP and GSK3ß expression at both mRNA and protein levels demonstrated that they are differently modulated during infection. NEP expression and enzymatic activity were initially stimulated but, with the progression of infection, they were down-regulated. In contrast, GSK3ß expression remained nearly unchanged, but the analysis of its phosphorylation suggests that it was inactivated only at later stages of HSV-1 infection. Thus, our data demonstrate that HSV-1 infection induces early upstream events in the cell that may eventually lead to Aß deposition and tau hyperphosphorylation and further suggest HSV-1 as a possible risk factor for AD.

Activation of 5-HT(2C) receptor promotes the expression of neprilysin in U251 human glioma cells.

Abeta accumulation, a hallmark of Alzheimer's disease, promotes the disease progress in multiple facets. Abeta is formed through amyloidogenic cleavage pathway of amyloid precursor protein (APP). Production of Abeta can be decreased via activation of 5-HT2C receptor, which enhances alternative APP non-amyloidogenic cleavage. Besides, as one of the best characterized Aß degrading enzymes, neprilysin (NEP) in AD progress has drawn more and more attention. We investigated whether there exists any connection between 5-HT2C receptor and NEP expression. The mRNA and protein expressions of NEP were increased after treatment of 5-HT2C receptor agonist RO-60-0175 in concentration- and time-dependent manners, and NEP expression was decreased after treatment of 5-HT2C receptor antagonist SB242084 correspondingly. These results suggest that 5-HT2C receptor may inhibit the Abeta formation by promoting NEP expression. The underlying mechanism will be explored in follow-up study and may provide potential target for AD therapy.

Withania somnifera reverses Alzheimer's disease pathology by enhancing low-density lipoprotein receptor-related protein in liver.

A 30-d course of oral administration of a semipurified extract of the root of Withania somnifera consisting predominantly of withanolides and withanosides reversed behavioral deficits, plaque pathology, accumulation of ß-amyloid peptides (Aß) and oligomers in the brains of middle-aged and old APP/PS1 Alzheimer's disease transgenic mice. It was similarly effective in reversing behavioral deficits and plaque load in APPSwInd mice (line J20). The temporal sequence involved an increase in plasma Aß and a decrease in brain Aß monomer after 7 d, indicating increased transport of Aß from the brain to the periphery. Enhanced expression of low-density lipoprotein receptor-related protein (LRP) in brain microvessels and the Aß-degrading protease neprilysin (NEP) occurred 14-21 d after a substantial decrease in brain Aß levels. However, significant increase in liver LRP and NEP occurred much earlier, at 7 d, and were accompanied by a rise in plasma sLRP, a peripheral sink for brain Aß. In WT mice, the extract induced liver, but not brain, LRP and NEP and decreased plasma and brain Aß, indicating that increase in liver LRP and sLRP occurring independent of Aß concentration could result in clearance of Aß. Selective down-regulation of liver LRP, but not NEP, abrogated the therapeutic effects of the extract. The remarkable therapeutic effect of W. somnifera mediated through up-regulation of liver LRP indicates that targeting the periphery offers a unique mechanism for Aß clearance and reverses the behavioral deficits and pathology seen in Alzheimer's disease models.

[ROLE OF CASPASE-3 IN REGULATION OF THE CONTENT OF THE AMYLOID-DEGRADING NEUROPEPTIDASE NEPRILYSIN IN THE CORTEX OF RATS AFTER HYPOXIA].

Analysis of the effect of a caspase-3 inhibitor on the content of the amyloid-degrading neuropeptidase neprilysin (NEP) in the cortex of rats subjected to prenatal hypoxia (7% O2, 3 h) on the 14-th day of the embryonic development (E14) was performed. It was found that rats subjected to prenatal hypoxia on days 20-30 after birth have an increased content and activity of caspase-3 with reduced levels of NEP and of the C-terminal fragment of the amyloid precursor protein (AICD) regulating NEP expression. In hypoxic animals 3 days after a single injection of a caspase inhibitor (i. v., Ac-DEVD-CHO, P20) the content of AICD and NEP was found to be increased up to the levels observed in control rats. The data obtained suggest that the increase of caspase-3 enzyme activity could affect NEP expression via proteolytic degradation of its transcription factor AICD. These data for the first time demonstrate the role of caspases in AICD-dependent regulation of NEP production in the brain of mammals under hypoxic conditions.

Hypoxia-inducible factor-1α mediates up-regulation of neprilysin by histone deacetylase-1 under hypoxia condition in neuroblastoma cells.

Hypoxia-inducible factor (HIF)-1 is the key transcriptional activator mediating both adaptive and pathological responses to hypoxia. The purpose of this study was to find the role of HIF-1 in regulating neprilysin (NEP) at the early stage of hypoxia and explore the underlying mechanism. In this study, we demonstrated that both NEP mRNA and protein levels in neuroblastoma cells were elevated in early stages of hypoxia. Over-expression of HIF-1α gene increased NEP mRNA/protein levels, as well as enzyme activity while knockdown of HIF-1α decreased them. Meanwhile, HIF-1α was shown to bind to histone deacetylase (HDAC)-1 and reduced the association of HDAC-1 with NEP promoter, thus activating NEP gene transcription in a de-repression way. In summary, our results indicated that hypoxia in the early stages would up-regulate NEP expression, in which interaction of HIF-1α and HDAC-1 may play a role. This study suggested that NEP up-regulation might be an adaptive response to hypoxia, which was mediated by HIF-1α binding to HDAC-1 at the early stage of hypoxia.

Mitochondria-targeted catalase reduces abnormal APP processing, amyloid ß production and BACE1 in a mouse model of Alzheimer's disease: implications for neuroprotection and lifespan extension.

The purpose of this study was to investigate the protective effects of the mitochondria-targeted antioxidant catalase (MCAT) and lifespan extension in mice that express amyloid beta (Aß). Using immunoblotting and immunostaining analyses, we measured the production of full-length amyloid precursor protein (APP), soluble APPα, C-terminal fragments CTF99 and CTF83, monomeric and oligomeric Aß, Aß deposits and beta site amyloid precursor protein cleaving enzyme 1 (BACE1), in different stages of disease progression in MCAT/AßPP and AßPP mice. Using quantitative reverse transcriptase polymerase chain reaction and immunostaining analyses, we studied the expression of catalase, BACE1, the Alzheimer's disease (AD) markers, synaptophysin, APP, neprilysin, insulin-degrading enzyme and transthyretin in MCAT, AßPP, MCAT/AßPP and wild-type (WT) mice. Using the high pressure liquid chromatography analysis of 8-hydroxy-2-deoxyguanosine, we measured oxidative DNA damage in the cerebral cortical tissues from MCAT, AßPP, MCAT/AßPP and WT mice. We found that the AßPP transgenic mice that carried the human MCAT gene lived 5 months longer than did the AßPP mice. We also found that the overexpression of MCAT in the brain sections from the MCAT/AßPP transgenic mice significantly correlated with a reduction in the levels of full-length APP, CTF99, BACE1, Aß levels (40 and 42), Aß deposits and oxidative DNA damage relative to the brain sections from the AßPP mice. Interestingly, we found significantly increased levels of soluble APPα and CTF83 in the MCAT/AßPP mice, relative to the AßPP mice. These data provide direct evidence that oxidative stress plays a primary role in AD etiopathology and that in MCAT mice express Aß, MCAT prevents abnormal APP processing, reduces Aß levels and enhances Aß-degrading enzymes in mice at different ages, corresponding to different stages of disease progression. These findings indicate that mitochondria-targeted molecules may be an effective therapeutic approach to treat patients with AD.