Lewy-like aggregation of α-synuclein reduces protein phosphatase 2A activity in vitro and in vivo

α-synuclein (α-Syn) is a chaperone-like protein that is highly implicated in Parkinson's disease (PD) as well as in dementia with Lewy bodies (DLB). Rare forms of PD occur in individuals with mutations of α-Syn or triplication of wild type α-Syn, and in both PD and DLB the intraneuronal inclusions known as Lewy bodies contain aggregated α-Syn that is highly phosphorylated on serine 129. In neuronal cells and in the brains of α-Syn overexpressing transgenic mice, soluble α-Syn stimulates the activity of protein phosphatase 2A (PP2A), a major serine/threonine phosphatase. Serine 129 phosphorylation of α-Syn attenuates its stimulatory effects on PP2A and also accelerates α-Syn aggregation; however, it is unknown if aggregation of α-Syn into Lewy bodies impairs PP2A activity. To assess for this, we measured the impact of α-Syn aggregation on PP2A activity in vitro and in vivo. In cell-free assays, aggregated α-Syn had ∼50% less PP2A stimulatory effects than soluble recombinant α-Syn. Similarly in DLB and α-Syn triplication brains, which contain robust α-Syn aggregation with high levels of serine 129 phosphorylation, PP2A activity was also ∼50% attenuated. As α-Syn normally stimulates PP2A activity, our data suggest that overexpression of α-Syn or sequestration of α-Syn into Lewy bodies has the potential to alter the phosphorylation state of key PP2A substrates; raising the possibility that all forms of synucleinopathy will benefit from treatments aimed at optimizing PP2A activity.

Bioequivalence evaluation of cefdinir in healthy fasting subjects

A simple and sensitive HPLC method was developed to determine cefdinir (CAS 91832-40-5) in human plasma. The method was validated by investigating the accuracy and precision for intra- and inter-day runs in a linear concentration from 0.05-2.0 µg/ml. The object of this study was to compare the bioavailability of cefdinir capsule (reference) and cefdinir granule (test) containing 100 mg of cefdinir. A randomized, open-label, single-dose, 2-way crossover bioequivalence study in 20 healthy, Chinese, male subjects was conducted. A 1-week wash-out period was applied. Blood samples were collected before and with 10 h after drug administration. The formulations were compared using the following pharmacokinetic parameters: AUC0-t, AUC0-∞ and C max. The 90% confidence interval (CI) of the ratios of log-transformed AUC0-t and AUC0-∞ were used to assess bioequivalence between the 2 formulations using the equivalence interval of 80 and 125%. The results showed that the 90% CI of the ratios of AUC0-t, AUC0-∞ and C max were 102.5% (94.7-111.0%), 103.4% (94.8-112.7%) and 106.4% (97.0-116.7%), respectively, which indicated 2 formulations of cefidinir are bioequivalent. Both treatments showed similar tolerability and safety.

Multidrug efflux pumps and cancer stem cells: insights into multidrug resistance and therapeutic development

Stem cells possess the dual properties of self-renewal and pluripotency. Self-renewal affords these populations the luxury of self-propagation, whereas pluripotency allows them to produce the multitude of cell types found in the body. Protection of the stem cell population from damage or death is critical because these cells need to remain intact throughout the life of an organism. The principal mechanism of protection is through expression of multifunctional efflux transporters--the adenosine triphosphate-binding cassette (ABC) transporters that are the "guardians" of the stem cell population. Ironically, it has been shown that these ABC efflux pumps also afford protection to cancer stem cells (CSCs), shielding them from the adverse effects of chemotherapeutic insult. It is therefore imperative to gain a better understanding of the mechanisms involved in the resistance of stem cells to chemotherapy, which could lead to the discovery of new therapeutic targets and improvement of current anticancer strategies.

TRPV4 mutations and cytotoxic hypercalcemia in axonal Charcot-Marie-Tooth neuropathies

OBJECTIVE

To improve understanding of TRPV4-associated axonal Charcot-Marie-Tooth (CMT) neuropathy phenotypes and their debated pathologic mechanism.

METHODS

A total of 17 CMT2C phenotypic families with vocal cord and diaphragmatic involvement and 36 clinically undifferentiated CMT2 subjects underwent sequencing analysis of the coding region of TRPV4. Functional studies of mutant proteins were performed using transiently transfected cells for TRPV4 subcellular localization, basal and stimulated Ca(2+) channel analysis, and cell viability assay with or without channel blockade.

RESULTS

Two TRPV4 mutations R232C and R316H from 17 CMT2C families were identified in the ankyrin repeat domains. The R316H is a novel de novo mutation found in a patient with CMT2C phenotype. The family with R232C mutation had individuals with and without vocal cord and diaphragm involvement. Both mutant TRPV4 proteins had normal subcellular localization in HEK293 and HeLa cells. Cells transfected with R232C and R316H displayed increased intracellular Ca(2+) levels and reversible cell death by the TRPV channel antagonist, ruthenium red.

CONCLUSION

TRPV4 ankyrin domain alterations including a novel de novo mutation cause axonal CMT2. Individuals with the same mutation may have nondistinct CMT2 or have phenotypic CMT2C with vocal cord paresis. Reversible hypercalcemic gain-of-function of mutant TRPV4 instead of loss-of-function appears to be pathologically important. The reversibility of cell death by channel blockade provides an attractive area of investigation in consideration of treatable axonal degeneration.

The Presence of Hepatitis B Surface Antigen in the Ova of Pregnant Women and Its Relationship with Intra-Uterine Infection by Hepatitis B Virus

Vertical transmission of hepatitis B virus (HBV) has been proposed to play an important role in mother-to-child transmission, although the extent to which vertical transmission via oocytes contributes to neonatal HBV infection remains unknown. Ovarian biopsies were collected during caesarean sections in 68 clinically asymptomatic pregnant women who were carriers of HBV. The presence of hepatitis B surface antigen (HBsAg) in the ova of pregnant women was determined by immunohistochemistry. Serum markers of HBV infection in pregnant women and their neonates were analysed. It was found that, of 68 women, the ova were positive for HBsAg in only one woman and her neonate was negative for any serum HBV markers 3 days after birth. Of 68 neonates, one was positive for serum HBV markers 3 days after birth and his mother's ova were negative for HBsAg. These findings indicate that vertical transmission via oocytes may not be the major route of HBV intra-uterine infection.

Diverse molecular functions of Hu proteins

Hu proteins are RNA-binding proteins involved in diverse biological processes. The neuronal members of the Hu family, HuB, HuC, and HuD play important roles in neuronal differentiation and plasticity, while the ubiquitously expressed family member, HuR, has numerous functions mostly related to cellular stress response. The pivotal roles of Hu proteins are dictated by their molecular functions affecting a large number of target genes. Hu proteins affect many post-transcriptional aspects of RNA metabolism, from splicing to translation. In this communication, we will focus on these molecular events and review our current understanding of how Hu proteins mediate them. In particular, emphasis will be put on the nuclear functions of these proteins, which were recently discovered. Three examples including calcitonin/calcitonin gene-related peptide, neurofibromatosis type 1, and Ikaros will be discussed in detail. In addition, an intriguing theme of antagonism between Hu proteins and other AU-rich sequence binding proteins will be discussed.

Nearly completely reversible brain abnormalities in a patient with incontinentia pigmenti

SUMMARY

We report a case of incontinentia pigmenti with reversible cortex and subcortical white matter necrosis-like presentation by MR imaging. The reversible changes in follow-up imaging of the patient with incontinentia pigmenti suggest a course of natural repair of inflammation or cerebrovascular disease.

Targeted therapy for cancer stem cells: the patched pathway and ABC transporters

Data from certain leukemias as well as brain and breast cancer indicate that there is a small population of tumor cells with "stem cell" characteristics and the capacity for self-renewal. The self-renewing cells have many of the properties of normal stem cells and have been termed "cancer stem cells". These cancer stem cells make up as few as 1% of the cells in a tumor, making them difficult to detect and study. Like normal stem cells, cancer stem cells have a number of properties permitting them to survive traditional cancer chemotherapy and radiation therapy. These cells express high levels of ATP-binding cassette (ABC) drug transporters, providing for a level of resistance; are relatively quiescent; have higher levels of DNA repair and a lowered ability to enter apoptosis. Combined cancer therapy approaches targeting the cancer stem cells and the non-stem cells may be developed with increased efficacy. Efforts to target the Hedgehog/Patched pathway, critical to embryonic growth and differentiation, and the ABCG2 drug efflux transporter will be presented.

Enhanced Efficacy of Cholesterol-Minus Sonic Hedgehog in Postnatal Skin

The role of Sonic hedgehog (Shh) as a morphogen in diverse developmental settings depends on covalent addition of cholesterol. In this study, expression of Shh lacking cholesterol stimulated hair growth with greater efficacy than native Shh, suggesting that Shh acts as a chemokine rather than a morphogen in this postnatal role. Thus, a structural modification that renders a morphogen ineffective in developmental models may have distinct advantages for postnatal applications.

Involvement of mitogen-activated protein kinases in adriamycin-induced cardiomyopathy

The current study investigated the phosphorylation of mitogen-activated protein kinases (MAPKs) as well as pro- and anti-apoptotic proteins in adriamycin (ADR)-induced cardiomyopathy (AIC) and heart failure in rats. Modulatory effects of antioxidant probucol on the activation of MAPKs were also examined. Male rats were administered with ADR (15 mg/kg body wt ip, over 2 wk) with and without probucol (120 mg/kg body wt for 4 wk ip). Hearts from these animals were studied at 1- to 24-h as well as at 3-wk posttreatment durations. In the 3-wk group, ADR depressed cardiac function, increased left ventricular end-diastolic pressure (LVEDP), and caused dyspnea and mortality. These changes were prevented by probucol. Phosphorylation of extracellular signal-regulated kinase (ERK)1/2, in the early stage of AIC, showed a biphasic response, with a maximum increase to 513% seen at 4 h, followed by a decrease to 66.8% at 3 wk after the last injection of ADR. Phosphorylation of p38 and c-Jun NH2-terminal kinases (JNKs) showed a steady increase through 2, 4, and 24 h and 3 wk (116% to 148%). In gene microarray analysis at 3 wk (heart failure stage), mRNA expression for both ERK1/2 and p38 kinases was decreased, whereas JNK mRNA was undetectable. Probucol completely prevented these MAPK changes. Activation of caspase-3 as well as the increase in the ratio of Bax to Bcl-xl were seen at early time points (1–24 h) as well as in the heart failure stage (3 wk). It is suggested that a transient increase in ERK1/2 at a shorter interval indicate an early adaptive response, and failure of this response corresponded with heart failure. In contrast, a gradual and persistent increase in p38 and JNK MAPKs as well as in caspase-3 and the Bax-to-Bcl-xl ratio may contribute in the initiation of apoptosis and progression of heart failure. Because probucol modulated changes in cellular signaling pathways and cardiac function, it is likely that oxidative stress plays a key role in AIC and heart failure.

Cytokines are not upregulated in adriamycin-induced cardiomyopathy and heart failure

Heart failure due to a variety of causes is accompanied by an upregulation of cytokines, such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6). Adriamycin-induced cardiomyopathy (AIC) and heart failure is an important clinical problem. The current study investigated the expression of these cytokines in AIC and heart failure in rats. Both early and late stages of AIC was produced in rats. Myocardial gene expressions for TNF-alpha, IL-1beta and IL-6 were examined with DNA microarrays and RT-PCR. Protein levels of these cytokines in both the plasma and the myocardium were also examined by ELISA. In the early stage, myocardial mRNA expression of IL-1beta showed significant increase at 4 and 24 h, peaking at 4 h, while TNF-alpha did not change and IL-6 was undetectable. The protein levels of these three genes did not show any upregulation in the plasma or the heart. In the late stage, heart failure was confirmed by clinical signs as well as homodynamic changes. In this stage, plasma protein levels for TNF-alpha, IL-1beta and IL-6 were not changed. However, myocardial TNF-alpha mRNA expression and protein levels were significantly decreased, while both IL-1beta mRNA and protein levels were not different compared to the control group. IL-6 mRNA expression was undetectable in both normal and adriamycin-treated hearts while its protein level was not changed by adriamycin. Positive control using lipopolysaccharides (LPS) treatment (0.5 mg/kg body weight) for 2 h resulted in a significant increase in these three cytokines in the heart and plasma. These data suggest that an upregulation of cytokines may not be involved in AIC. Heart failure may in fact be accentuated by a downregulation of myocardial TNF-alpha.

Alkaloids and flavonoids from peanut skins

Separation of the water-soluble fraction of peanut skins led to the isolation of 8 flavonoids and two novel indole alkaloids. Two new flavonoid glycosides have been identified as isorhamnetin 3-O-[2-O-beta-glucopyranosyl-6-O-alpha-rhamnopyranosyl]- beta-glucopyranoside and 3',5,7-trihydroxyisoflavone-4'-methoxy-3'-O-beta-glucopyranoside. Two alkaloids are 2-methoxyl-3-(3-indolyl)-propionic acid and 2-hydroxyl-3-[3-(1-N-methyl)-indolyl]-propionic acid. These isolated flavonoids were evaluated for their free radical scavenging activity and protein glycation inhibitory effects.

Alternative ribonucleic acid processing in endocrine systems

Alternative RNA processing is a mechanism for creation of protein diversity through selective inclusion or exclusion of RNA sequence during posttranscriptional processing. More than one-third of human pre-mRNAs undergo alternative RNA processing modification, making this a ubiquitous biological process. The protein isoforms produced have distinct and sometimes opposite functions, underscoring the importance of this process. This review focuses on important endocrine genes regulated by alternative RNA processing. We discuss how diverse events such as spermatogenesis or GH action are regulated by this process. We focus on several endocrine (calcitonin/calcitonin gene-related peptide) and nonendocrine (Drosophila doublesex and P-element and mouse c-src) examples to highlight recent progress in the elucidation of molecular mechanisms regulating this process. Finally, we outline methods (model systems and techniques) used by investigators in this field to study processing of individual pre-mRNAS:

Localization of the gD-binding region of the human herpes simplex virus receptor, HveA

During virus entry, herpes simplex virus (HSV) glycoprotein D (gD) binds to one of several human cellular receptors. One of these, herpesvirus entry mediator A (HveA), is a member of the tumor necrosis factor receptor (TNFR) superfamily, and its ectodomain contains four characteristic cysteine-rich pseudorepeat (CRP) elements. We previously showed that gD binds the ectodomain of HveA expressed as a truncated, soluble protein [HveA(200t)]. To localize the gD-binding domain of HveA, we expressed three additional soluble forms of HveA consisting of the first CRP [HveA(76t)], the second CRP [HveA(77-120t)], or the first and second CRPs [HveA(120t)]. Biosensor and enzyme-linked immunosorbent assay studies showed that gD bound to HveA(120t) and HveA(200t) with the same affinity. However, gD did not bind to HveA(76t) or HveA(77-120t). Furthermore, HveA(200t) and HveA(120t), but not HveA(76t) or HveA(77-120t), blocked herpes simplex virus (HSV) entry into CHO cells expressing HveA. We also generated six monoclonal antibodies (MAbs) against HveA(200t). MAbs CW1, -2, and -4 bound linear epitopes within the second CRP, while CW7 and -8 bound linear epitopes within the third or fourth CRPs. None of these MAbs blocked the binding of gD to HveA. In contrast, MAb CW3 recognized a discontinuous epitope within the first CRP of HveA, blocked the binding of gD to HveA, and exhibited a limited ability to block virus entry into cells expressing HveA, suggesting that the first domain of HveA contains at least a portion of the gD binding site. The inability of gD to bind HveA(76t) suggests that additional amino acid residues of the gD binding site may reside within the second CRP.

Localization of a binding site for herpes simplex virus glycoprotein D on herpesvirus entry mediator C by using antireceptor monoclonal antibodies

The human herpesvirus entry mediator C (HveC), also known as the poliovirus receptor-related protein 1 (PRR1) and as nectin-1, allows the entry of herpes simplex virus type 1 (HSV-1) and HSV-2 into mammalian cells. The interaction of virus envelope glycoprotein D (gD) with such a receptor is an essential step in the process leading to membrane fusion. HveC is a member of the immunoglobulin (Ig) superfamily and contains three Ig-like domains in its extracellular portion. The gD binding site is located within the first Ig-like domain (V domain) of HveC. We generated a panel of monoclonal antibodies (MAbs) against the ectodomain of HveC. Eleven of these, which detect linear or conformational epitopes within the V domain, were used to map a gD binding site. They allowed the detection of HveC by enzyme-linked immunosorbent assay, Western blotting, and biosensor analysis or directly on the surface of HeLa cells and human neuroblastoma cell lines, as well as simian Vero cells. The anti-HveC V-domain MAbs CK6, CK8, and CK41, as well as the previously described MAb R1.302, blocked HSV entry. Their binding to soluble HveC was blocked by the association of gD with the receptor, indicating that their epitopes overlap a gD binding site. Competition assays on an optical biosensor showed that CK6 and CK8 (linear epitopes) inhibited the binding of CK41 and R1.302 (conformational epitopes) to HveC and vice versa. Epitope mapping showed that CK6 and CK8 bound between residues 80 and 104 of HveC, suggesting that part of the gD binding site colocalizes in the same region.

Green tea polyphenols induce apoptosis in vitro in peripheral blood T lymphocytes of adult T-cell leukemia patients

Green tea polyphenols (TEA) are known to exhibit antioxidative activity as well as tumor-suppressing activity. In order to examine the tumor-suppressing activity of TEA against adult T-cell leukemia (ATL), we cultivated peripheral blood T lymphocytes of ATL patients (ATL PBLs), an HTLV-I-infected T-cell line (KODV) and healthy controls (normal PBLs) for 3 days in the presence of TEA and its main constituent, epigallocatechin-3-gallate (EGCg), to measure cell proliferation and apoptosis, and to quantitate mRNAs of HTLV-I pX and beta-actin genes of the cultured cells. Growth of ATL PBLs was significantly inhibited by 9-27 microg/ml of TEA and EGCg, in contrast to minimal growth inhibition of T cells of normal PBLs. Inhibition of KODV was intermediate between ATL PBLs and normal PBLs. The ATL PBLs and KODV treated with 27 microg/ml of either TEA or EGCg induced apoptotic DNA fragmentation, producing terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells, while the normal PBLs treated with the same concentration of TEA or EGCg produced a negligibly small number of TUNEL-positive cells, in which apoptotic DNA fragmentation was not detectable. Expression of HTLV-I pX mRNA was suppressed more than 90% in ATL PBLs by treatment with 3-27 microg/ml of either TEA or EGCg, while expression of beta-actin mRNA was much less suppressed by treatment with the same concentration of TEA or EGCg. These results indicate that TEA and EGCg inhibit growth of ATL PBLs, as well as HTLV-I-infected T-cells, by suppressing HTLV-I pX gene expression and inducing apoptotic cell death.

The presence of ancient human T-cell lymphotropic virus type I provirus DNA in an Andean mummy

The worldwide geographic and ethnic clustering of patients with diseases related to human T-cell lymphotropic virus type I (HTLV-I) may be explained by the natural history of HTLV-I infection. The genetic characteristics of indigenous people in the Andes are similar to those of the Japanese, and HTLV-I is generally detected in both groups. To clarify the common origin of HTLV-I in Asia and the Andes, we analyzed HTLV-I provirus DNA from Andean mummies about 1,500 years old. Two of 104 mummy bone marrow specimens yielded a band of human beta-globin gene DNA 110 base pairs in length, and one of these two produced bands of HTLV-I-pX (open reading frame encoding p40x, p27x) and HTLV-I-LTR (long terminal repeat) gene DNA 159 base pairs and 157 base pairs in length, respectively. The nucleotide sequences of ancient HTLV-I-pX and HTLV-I-LTR clones isolated from mummy bone marrow were similar to those in contemporary Andeans and Japanese, although there was microheterogeneity in the sequences of some mummy DNA clones. This result provides evidence that HTLV-I was carried with ancient Mongoloids to the Andes before the Colonial era. Analysis of ancient HTLV-I sequences could be a useful tool for studying the history of human retroviral infection as well as human prehistoric migration.

The major neutralizing antigenic site on herpes simplex virus glycoprotein D overlaps a receptor-binding domain

Herpes simplex virus (HSV) entry is dependent on the interaction of virion glycoprotein D (gD) with one of several cellular receptors. We previously showed that gD binds specifically to two structurally dissimilar receptors, HveA and HveC. We have continued our studies by using (i) a panel of baculovirus-produced gD molecules with various C-terminal truncations and (ii) a series of gD mutants with nonoverlapping 3-amino-acid deletions between residues 222 and 254. Binding of the potent neutralizing monoclonal antibody (MAb) DL11 (group Ib) was unaffected in forms of gD containing residues 1 to 250 but was greatly diminished in molecules truncated at residue 240 or 234. Both receptor binding and blocking of HSV infection were also affected by these C-terminal truncations. gD-1(234t) bound weakly to both HveA and HveC as determined by enzyme-linked immunosorbent assay (ELISA) and failed to block infection. Interestingly, gD-1(240t) bound well to both receptors but blocked infection poorly, indicating that receptor binding as measured by ELISA is not the only gD function required for blocking. Optical biosensor studies showed that while gD-1(240t) bound HveC with an affinity similar to that of gD-1(306t), the rates of complex formation and dissociation were significantly faster than for gD-1(306t). Complementation analysis showed that any 3-amino-acid deletion between residues 222 and 251 of gD resulted in a nonfunctional protein. Among this set of proteins, three had lost DL11 reactivity (those with deletions between residues 222 and 230). One of these proteins (deletion 222-224) was expressed as a soluble form in the baculovirus system. This protein did not react with DL11, bound to both HveA and HveC poorly as shown by ELISA, and failed to block HSV infection. Since this protein was bound by several other MAbs that recognize discontinuous epitopes, we conclude that residues 222 to 224 are critical for gD function. We propose that the potent virus-neutralizing activity of DL11 (and other group Ib MAbs) likely reflects an overlap between its epitope and a receptor-binding domain of gD.