Dopaminergic but not cholinergic neurodegeneration is correlated with gait disturbances in PINK1 knockout rats

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by gait dysfunction in later stages of the disease. PD hallmarks include a decrease in stride length, run speed, and swing time; an increase in stride time, stance time, and base of support; dopaminergic degeneration in the basal ganglia; and cholinergic degeneration in the pedunculopontine nucleus (PPN). A progressive animal model of PD is needed to identify treatments for gait dysfunction. The goal of this study was to quantify progressive gait degeneration in PTEN-induced putative kinase 1 knockout (P1KO) rats and investigate neurodegeneration as potential underlying mechanisms. Gait analysis was performed in male P1KO and wild-type rats at 5 and 8 months of age and immunohistochemical analysis at 8 months. Multiple parameters of volitional gait were measured using a runway system. P1KO rats exhibited significant gait deficits at 5 months, but not 8 months. Gait abnormalities improved over time suggesting compensation during behavioral testing. At 8 months a 15% loss of tyrosine hydroxylase (TH) in the striatum, a 27% loss of TH-positive cells in the substantia nigra pars compacta, and no significant loss of choline acetyltransferase-positive cells in the PPN was found. Dopaminergic cell loss may contribute to gait deficits in the P1KO model, but not cholinergic cell loss. The P1KO rat with the greatest dopamine loss exhibited the most pronounced PD-like gait deficits, highlighting variability within the model. Further analysis is required to determine the suitability of the P1KO rat as a progressive model of gait abnormalities in PD.

Development of an optimized freeze-drying protocol for OM-PBAE nucleic acid polyplexes

Long-term stability of polyplexes used for biomedical purposes is an objective envisaged by any research group developing this kind of nanoformulations. However, since biodegradable polymers such as oligopeptide end-modified poly (β-aminoester) (OM-PBAE) are frequently used to ensure safety, and formulations are produced as aqueous dispersions, the stability of the nanoformulations is usually compromised. In this context, freeze-drying has aroused as a promising storage alternative to obtain solid nanoformulations with enhanced stability over time. Lyophilization is a challenging step that usually produces aggregation. Although some studies already achieved freeze-dried PBAE nanoparticles, none of them detailed the parameters that are critical for the success of this process. Moreover, due to the specific composition of each formulation, the critical parameters for the correct freeze-drying process need to be adjusted for each polyplex developed. In this paper, we have studied the variables that have a direct influence on the manufacturing and lyophilization of OM-PBAE nanoparticles with the aim to develop a versatile and robust freeze-drying receipt that properly preserves the library of polyplexes designed in our group, which have different pKa depending on the modification applied.

Synthesis and evaluation of new quinazolin-4(3H)-one derivatives as potent antibacterial agents against multidrug resistant Staphylococcus aureus and Mycobacterium tuberculosis

Staphylococcus aureus and Mycobacterium tuberculosis are major causative agents responsible for serious nosocomial and community-acquired infections impacting healthcare systems globally. Over several decades, these pathogens have developed resistance to multiple antibiotics significantly affecting morbidity and mortality. Thus, these recalcitrant pathogens are amongst the most formidable microbial pathogens for which international healthcare agencies have mandated active identification and development of new antibacterial agents for chemotherapeutic intervention. In our present work, a series of new quinazolin-4(3H)-one derivatives were designed, synthesized and evaluated for their antibacterial activity against ESKAP pathogens and pathogenic mycobacteria. The experiments revealed that 4'c, 4'e, 4'f and 4'h displayed selective and potent inhibitory activity against Staphylococcus aureus with MIC values ranging from 0.03-0.25 μg/mL. Furthermore, compounds 4'c and 4'e were found to be benign to Vero cells (CC₅₀ = >5 μg/mL) and displayed promising selectivity index (SI) > 167 and > 83.4 respectively. Additionally, 4'c and 4'e demonstrated equipotent MIC against multiple drug-resistant strains of S. aureus including VRSA, concentration dependent bactericidal activity against S. aureus and synergized with FDA approved drugs. Moreover, compound 4'c exhibited more potent activity in reducing the biofilm and exhibited a PAE of ∼2 h at 10X MIC which is comparable to levofloxacin and vancomycin. In vivo efficacy of 4'c in murine neutropenic thigh infection model revealed that 4'c caused a similar reduction in cfu as vancomycin. Gratifyingly, compounds 4d, 4e, 9a, 9b, 14a, 4'e and 4'f also exhibited anti-mycobacterial activity with MIC values in the range of 2-16 μg/mL. In addition, the compounds were found to be less toxic to Vero cells (CC₅₀ = 12.5->100 μg/mL), thus displaying a favourable selectivity index. The interesting results obtained here suggest the potential utilization of these new quinazolin-4(3H)-one derivatives as promising antibacterial agents for treating MDR-Staphylococcal and mycobacterial infections.

In vitro inactivation of Mycobacterium avium subsp. paratuberculosis (MAP) by use of copper ions

Background

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of paratuberculosis, a contagious infectious disease that affects domestic and wild ruminants causing chronic inflammation of the intestine. MAP has proven to be very resistant to both physical and chemical processes, making it difficult to control this pathogen. Based on the recognized antimicrobial properties of copper, the objective of this study was to evaluate the effectiveness of copper ions to reduce MAP numbers and/or MAP viability in a fluid matrix. Besides, methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli were used as controls of the effectiveness of copper ions. MAP-spiked PBS was subjected to copper ions treatment at 24 V for 5 min and the PBS suspensions were sampled before and after treatment. MAP viability and quantification were determined using three complementary techniques: a phage amplification assay, MGIT culture and qPCR.

Results

Moderate numbers (10³ CFU ml⁻¹) of the two control bacteria were completely eliminated by treatment with copper ions. For MAP, copper ions treatment reduced both the viability and numbers of this pathogen. Phage assay information quickly showed that copper ions (24 V for 5 min) resulted in a significant reduction in viable MAP. MGIT culture results over time showed statistically significant differences in time-to-detection (TTD) values between PRE and POST treatment. MAP genome equivalent estimates for PBS suspensions indicated that MAP numbers were lower in samples POST-treatment with copper ions than PRE-treatment.

Conclusions

The use of copper ions resulted in a significant reduction of MAP in a liquid matrix, although some MAP survival on some occasions was observed.

Comparison of Eight Cell-Free Media for Maintenance of Toxoplasma gondii Tachyzoites

BACKGROUND

Toxoplasmosis is considered as one of the most common infectious diseases caused by the protozoan parasite Toxoplasma gondii. Tachyzoite is the main form of Toxoplasma and continuously is maintained in cell culture or injected into the mice peritoneal cavity. This study was designed to evaluate the survival rate of RH strain of T. gondii tachyzoites in different cell free, nutrient and biological media at different temperatures.

METHODS

This experimental study was performed at the Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran, in 2010. One ml of each solution including hypotonic saline (0.3%), normal saline (0.85%), RPMI-1640 (RPMI), RPMI with 10% fetal bovine serum (FBS), RPMI with 20% FBS, ovine hydatid cyst fluid, pasteurized milk of cow, and phosphate buffered saline (PBS) along with 4×10(4) T. gondii tachyzoites were added to plate wells and incubated in 4 °C, 22 °C, 37 °C, and 37 °C under 5% CO2. The survival rate and viability assessment of parasites were performed daily and the results were analyzed using Univariate tests.

RESULT

Tachyzoites survival rate in PBS (4 °C) and normal saline (4 °C) were considerably high, compared to other solutions in different conditions (P<0.001). The best temperature for Toxoplasma maintenance was 4 °C (P<0.001).

CONCLUSION

This study introduces two available and economical solutions, PBS (4 °C) and normal saline (4 °C) media, for maintenance of Toxoplasma tachyzoites as appropriate choice media for a noticeable period of time (11 days) in vitro.

Characteristics of silver nanoparticles in vehicles for biological applications

Silver nanoparticles (AgNPs) have been used for decades as anti-bacterial agents in various industrial fields such as cosmetics, health industry, food storage, textile coatings and environmental applications, although their toxicity is not fully recognized yet. Antimicrobial and catalytic activity of AgNPs depends on their size as well as structure, shape, size distribution, and physico-chemical environment. The unique properties of AgNPs require novel or modified toxicological methods for evaluation of their toxic potential combined with robust analytical methods for characterization of nanoparticles applied in relevant vehicles, e.g., culture medium with/without serum and phosphate buffered saline.

Combination use of ferulic acid, ligustrazine and tetrahydropalmatine inhibits the growth of ectopic endometrial tissue: a multi-target therapy for endometriosis rats

ETHNOPHARMACOLOGICAL RELEVANCE

Ferulic acid (FA), ligustrazine (LZ) and tetrahydropalmatine (THP) are separately isolated from Chinese Angelica, Szechwan Lovage Rhizome and Rhizoma in the Jiawei-Foshou-San formula, a popular traditional Chinese medicine for irregular menses. It has been reported that the combination use of FA+LZ+THP has similar effect on endometriosis, but the underlying mechanisms are unclear. This study was to investigate the combination effects and mechanisms of FA+LZ+THP on endometriosis rats.

MATERIALS AND METHODS

Fifty endometriosis rats were intragastricly treated with FA+LZ+THP for 4 wk. The volume of ectopic endometrial tissue was measured to evaluate the effects. Then the changes in hypothalamic-pituitary-ovarian axis and ERE pathway were indicated by the levels of E2, GnRH, FSH and LH, and the expressions of ER, HSP90 and COX-2, respectively. In addition, peritoneal macrophages of each rat were cultured in vitro and treated with (FA+LZ+THP)-medicated serum for 24h. The proliferation and phagocytosis abilities, the levels of IL-1β and TNF-α, and the expression of IκBα were then measured for the changes of peritoneal macrophage activities.

RESULTS

Combination use of FA+LZ+THP diminished the volume of the ectopic endometrial tissues (P<0.05 or P<0.01). It also decreased the E2 level, suppressed the expression of GnRH, FSH and LH, and decreased the protein expression of ER, HSP90 and COX-2 (all P<0.05 or P<0.01). The phagocytosis ability of peritoneal macrophage was enhanced by (FA+LZ+THP)-medicated serum (P<0.05) with no change of proliferation (P>0.05). Moreover, IL-1β and TNF-α were downregulated (both P<0.05 or P<0.01) and IκBα was upregulated by the (FA+LZ+THP)-medicated serum (P<0.01).

CONCLUSIONS

The combination use of FA, LZ and THP could inhibit the growth of ectopic endometrial tissue in endometriosis rats. It might be related to the down-regulation of hypothalamic-pituitary-ovarian axis, the amelioration in ERE pathway and the improvement of peritoneal macrophage activities.

Applicability of dynamic membrane technology in anaerobic membrane bioreactors

This study investigated the applicability of dynamic membrane technology in anaerobic membrane bioreactors for the treatment of high strength wastewaters. A monofilament woven fabric was used as support material for dynamic membrane formation. An anaerobic dynamic membrane bioreactor (AnDMBR) was operated under a variety of operational conditions, including different sludge retention times (SRTs) of 20 and 40 days in order to determine the effect of SRT on both biological performance and dynamic membrane filtration characteristics. High COD removal efficiencies exceeding 99% were achieved during the operation at both SRTs. Higher filtration resistances were measured during the operation at SRT of 40 days in comparison to SRT of 20 days, applying a stable flux of 2.6 L/m(2) h. The higher filtration resistances coincided with lower extracellular polymeric substances concentration in the bulk sludge at SRT of 40 days, likely resulting in a decreased particle flocculation. Results showed that dynamic membrane technology achieved a stable and high quality permeate and AnDMBRs can be used as a reliable and satisfactory technology for treatment of high strength wastewaters.

Nonstructural proteins of Torque teno sus virus 2 from O2AUG: prediction to experimental validation

The expression profiles of nonstructural proteins (NSPs) in Torque teno sus virus 2 (TTSuV2) have not yet been characterized. Here, we determined the coding sequences of the TTSuV2 NSPs ORF2, ORF2/2, and ORF2/2/3 by overlapping polymerase chain reaction (PCR) and subsequent expression in bacterial and mammalian cells. We generated two monoclonal antibodies (mAbs), 2E5 and 6F8, from mice immunized with mixed Escherichia coli expressing His-tagged ORF2 and ORF2/2. Enzyme-linked immunosorbent assay (ELISA) and western blot analysis revealed that, 2E5 mAbs bound to the consensus sequences of ORF2, ORF2/2, and ORF2/2/3, while 6F8 recognized the common sequences of ORF2/2 and ORF2/2/3. Immunofluorescence assay (IFA) revealed that ORF2 was localized in the cytoplasm, ORF2/2, in the nucleus but not the nucleolus, and ORF2/2/3, in the peri-nuclear region. To identify the expression profiles of TTSuV NSPs, a circular TTSuV2_ZJ (GenBank: KF660540) genomic DNA clone was constructed and transfected into HEK293T and HeLa cells. Splicing mRNAs and the expression and localization of ORF2/2 and ORF2/2/3 were identified by RT-PCR, western blot analysis, and IFA, respectively. However, ORF2 was not detected either at the RNA or protein level. Our study is the first to provide experimental evidence of the existence of ORF2/2 and ORF2/2/3 at the protein level. Moreover, the mAbs have potential applications in future research on TTSuV2 viral protein function and diagnosis of related diseases.

Comparative gene expression analysis of Dtg, a novel target gene of Dpp signaling pathway in the early Drosophila melanogaster embryo

In the early Drosophila melanogaster embryo, Dpp, a secreted molecule that belongs to the TGF-β superfamily of growth factors, activates a set of downstream genes to subdivide the dorsal region into amnioserosa and dorsal epidermis. Here, we examined the expression pattern and transcriptional regulation of Dtg, a new target gene of Dpp signaling pathway that is required for proper amnioserosa differentiation. We showed that the expression of Dtg was controlled by Dpp and characterized a 524-bp enhancer that mediated expression in the dorsal midline, as well as, in the differentiated amnioserosa in transgenic reporter embryos. This enhancer contained a highly conserved region of 48-bp in which bioinformatic predictions and in vitro assays identified three Mad binding motifs. Mutational analysis revealed that these three motifs were necessary for proper expression of a reporter gene in transgenic embryos, suggesting that short and highly conserved genomic sequences may be indicative of functional regulatory regions in D. melanogaster genes. Dtg orthologs were not detected in basal lineages of Dipterans, which unlike D. melanogaster develop two extra-embryonic membranes, amnion and serosa, nevertheless Dtg orthologs were identified in the transcriptome of Musca domestica, in which dorsal ectoderm patterning leads to the formation of a single extra-embryonic membrane. These results suggest that Dtg was recruited as a new component of the network that controls dorsal ectoderm patterning in the lineage leading to higher Cyclorrhaphan flies, such as D. melanogaster and M. domestica.

Regulation of platelet responses triggered by Toll-like receptor 2 and 4 ligands is another non-genomic role of nuclear factor-kappaB

INTRODUCTION

Platelets express Toll-like receptors (TLRs) that recognise molecular components of pathogens and, in nucleated cells, elicit immune responses through nuclear factor-kappaB (NF-κB) activation. We have shown that NF-κB mediates platelet activation in response to classical agonists, suggesting that this transcription factor exerts non-genomic functions in platelets. The aim of this study was to determine whether NF-κB activation is a downstream signal involved in TLR2 and 4-mediated platelet responses.

MATERIAL AND METHODS

Aggregation and ATP release were measured with a Lumi-aggregometer. Fibrinogen binding, P-selectin and CD40 ligand (CD40L) levels and platelet-neutrophil aggregates were measured by cytometry. I kappa B alpha (IκBα) degradation and p65 phosphorylation were determined by Western blot and von Willebrand factor (vWF) by ELISA.

RESULTS

Platelet stimulation with Pam3CSK4 or LPS resulted in IκBα degradation and p65 phosphorylation. These responses were suppressed by TLR2 and 4 blocking and synergised by thrombin. Aggregation, fibrinogen binding and ATP and vWF release were triggered by Pam3CSK4. LPS did not induce platelet responses per se, except for vWF release, but it did potentiate thrombin-induced aggregation, fibrinogen binding and ATP secretion. Pam3CSK4, but not LPS, induced P-selectin and CD40L expression and mixed aggregate formation. All of these responses, except for CD40L expression, were inhibited in platelets treated with the NF-κB inhibitors BAY 11-7082 or Ro 106-9920.

CONCLUSION

TLR2 and 4 agonists trigger platelet activation responses through NF-κB. These data show another non-genomic function of NF-κB in platelets and highlight this molecule as a potential target to prevent platelet activation in inflammatory or infectious diseases.

Carbon nanotubes for delivery of small molecule drugs

In the realm of drug delivery, carbon nanotubes (CNTs) have gained tremendous attention as promising nanocarriers, owing to their distinct characteristics, such as high surface area, enhanced cellular uptake and the possibility to be easily conjugated with many therapeutics, including both small molecules and biologics, displaying superior efficacy, enhanced specificity and diminished side effects. While most CNT-based drug delivery system (DDS) had been engineered to combat cancers, there are also emerging reports that employ CNTs as either the main carrier or adjunct material for the delivery of various non-anticancer drugs. In this review, the delivery of small molecule drugs is expounded, with special attention paid to the current progress of in vitro and in vivo research involving CNT-based DDSs, before finally concluding with some consideration on inevitable complications that hamper successful disease intervention with CNTs.

Tyrosine residues play an important role in heme detoxification by serum albumin

BACKGROUND

Serum albumin binds avidly to heme to form heme-serum albumin complex, also called methemalbumin, and this binding is thought to protect against the potentially toxic effects of heme. However, the mechanism of detoxification has not been fully elucidated.

METHODS

SDS-PAGE and Western blot were used to determine the efficiency of methemalbumin on catalyzing protein carbonylation and nitration. HPLC was used to test the formation of heme to protein cross-linked methemalbumin.

RESULTS

The peroxidase activity of heme increased upon human serum albumin (HSA) binding. Methemalbumin showed higher efficiency in catalyzing tyrosine oxidation than free heme in the presence of H2O2. Methemalbumin catalyzed self-nitration and significantly promoted the nitration of tyrosine in coexistent protein, but decreased the carbonylation of coexistent protein compared with heme. The heme to protein cross-linked form of methemalbumin suggested that HSA trapped the free radical accompanied by the formation of ferryl heme. When tyrosine residues in HSA were modified by iodination, HSA lost of protection effect on protein carbonylation. The low concentration of glutathione could effectively inhibit tyrosine nitration, but had no effect on protein carbonylation.

CONCLUSION

HSA protects against the toxic effect of heme by transferring the free radical to tyrosine residues in HSA, therefore protecting surrounding proteins from irreversible oxidation, rather than by direct inhibiting the peroxidase activity. The increased tyrosine radicals can be reduced by endogenic antioxidants such as GSH.

GENERAL SIGNIFICANCE

This investigation indicated the important role of tyrosine residues in heme detoxification by HSA and suggested a possible novel mechanism.

ALG1-CDG: a new case with early fatal outcome

Congenital disorders of glycosylation (CDG) are a growing group of inherited metabolic disorders where enzymatic defects in the formation or processing of glycolipids and/or glycoproteins lead to variety of different diseases. The deficiency of GDP-Man:GlcNAc2-PP-dolichol mannosyltransferase, encoded by the human ortholog of ALG1 from yeast, is known as ALG1-CDG (CDG-Ik). The phenotypical, molecular and biochemical analysis of a severely affected ALG1-CDG patient is the focus of this paper. The patient's main symptoms were feeding problems and diarrhea, profound hypoproteinemia with massive ascites, muscular hypertonia, seizures refractory to treatment, recurrent episodes of apnoea, cardiac and hepatic involvement and coagulation anomalies. Compound heterozygosity for the mutations c.1145T>C (M382T) and c.1312C>T (R438W) was detected in the patient's ALG1-coding sequence. In contrast to a previously reported speculation on R438W we confirmed both mutations as disease-causing in ALG1-CDG.

The influence of immunosuppressive drugs on neural stem/progenitor cell fate in vitro

In allogenic and xenogenic transplantation, adequate immunosuppression plays a major role in graft survival, especially over the long term. The effect of immunosuppressive drugs on neural stem/progenitor cell fate has not been sufficiently explored. The focus of this study is to systematically investigate the effects of the following four different immunotherapeutic strategies on human neural progenitor cell survival/death, proliferation, metabolic activity, differentiation and migration in vitro: (1) cyclosporine A (CsA), a calcineurin inhibitor; (2) everolimus (RAD001), an mTOR-inhibitor; (3) mycophenolic acid (MPA, mycophenolate), an inhibitor of inosine monophosphate dehydrogenase and (4) prednisolone, a steroid. At the minimum effective concentration (MEC), we found a prominent decrease in hNPCs' proliferative capacity (BrdU incorporation), especially for CsA and MPA, and an alteration of the NAD(P)H-dependent metabolic activity. Cell death rate, neurogenesis, gliogenesis and cell migration remained mostly unaffected under these conditions for all four immunosuppressants, except for apoptotic cell death, which was significantly increased by MPA treatment.

Hypoxia stimulates 18F-fluorodeoxyglucose uptake in breast cancer cells via hypoxia inducible factor-1 and AMP-activated protein kinase

INTRODUCTION

Hypoxia can stimulate (18)F-fluorodeoxyglucose (FDG) uptake in cultured cells. A better understanding of the underlying molecular mechanism is required to determine the value of FDG for studying tumour hypoxia.

METHODS

The effect of hypoxia on FDG uptake, and key proteins involved in glucose transport and glycolysis, was studied in MCF7 and MDA231 breast cancer cell lines.

RESULTS

Hypoxia induced a dose- and time-dependent increase in FDG uptake. The FDG increase was transient, suggesting that FDG uptake is only likely to be increased by acute hypoxia (<24 h). Molecular analysis indicated that hypoxia upregulated glut1 and 6-phosphofructo-2-kinase, key proteins involved in regulating glucose transport and glycolysis, and that these changes were induced by Hypoxia-Inducible factor 1 (HIF1) upregulation and/or AMP-activated protein kinase activation.

CONCLUSIONS

FDG may provide useful information about the oxygenation status of cells in hypoxic regions where HIF1 upregulation is hypoxia-driven.

Major cis-regulatory elements for rice bidirectional promoter activity reside in the 5'-untranslated regions

Bidirectional promoters are defined as those that regulate adjacent genes organized in a divergent fashion (head to head orientation) and separated by <1 kb. In order to dissect bidirectional promoter activity in a model plant, deletion analysis was performed for seven rice promoters using promoter-reporter gene constructs, which identified three promoters to be bidirectional. Regulatory elements located in or close to the 5'-untranslated regions (UTR) of one of the genes (divergent gene pair) were found to be responsible for their bidirectional activity. DNA footprinting analysis identified unique protein binding sites in these promoters. Deletion/alteration of these motifs resulted in significant loss of expression of the reporter genes on either side of the promoter. Changes in the motifs at both the positions resulted in a remarkable decrease in bidirectional activity of the reporter genes flanking the promoter. Based on our results, we propose a novel mechanism for the bidirectionality of rice bidirectional promoters.

A novel peptide nanomedicine for treatment of pancreatogenic diabetes

Pancreatogenic diabetes (PD) is a potentially fatal disease that occurs secondary to pancreatic disorders. The current anti-diabetic therapy for PD is fraught with adverse effects that can increase morbidity. Here we investigated the efficacy of novel peptide nanomedicine: pancreatic polypeptide (PP) in sterically stabilized micelles (SSM) for management of PD. PP exhibits significant anti-diabetic efficacy but its short plasma half-life curtails its therapeutic application. To prolong and improve activity of PP in vivo, we evaluated the delivery of PP in SSM. PP-SSM administered to rats with PD, significantly improved glucose tolerance, insulin sensitivity and hepatic glycogen content compared to peptide in buffer. The studies established the importance of micellar nanocarriers in protecting enzyme-labile peptides in vivo and delivering them to target site, thereby enhancing their therapeutic efficacy. In summary, this study demonstrated that PP-SSM is a promising novel anti-diabetic nanomedicine and therefore should be further developed for management of PD.

FROM THE CLINICAL EDITOR

Pancreatic peptide was earlier demonstrated to address pancreatogenic diabetes, but its short half-life represented major difficulties in further development for therapeutic use. PP-SSM (pancreatic polypeptide in sterically stabilized micelles) is a promising novel anti-diabetic nanomedicine that enables prolonged half-life and increased bioactivity of PP, as shown in this novel study, paving the way toward clinical studies in the near future.