Mathematical modeling of cell growth in a 3D scaffold and validation of static and dynamic cultures

Tissue engineering, an immensely important field in contemporary clinical practices, aims at the repair or replacement of damaged tissues. The mathematical model proposed herein shows the distribution and growth of cells in their characteristic time in a 3D scaffold model. This study contributes to the progress of simulation techniques in static and dynamic cultures of bone tissue. Brinkman, nutrient transport, and cell growth equations are brought together to quantify the growth behavior of cells. However, when a static culture is being studied, the Brinkman equation is eliminated. The model was validated by experimental cell culture using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay and scanning electron microscopy. Then, static and dynamic cultures were compared to assess the cell density and cell distribution in the scaffold. Cell counting after 21 days of cell culture showed that the number of cells increased 42‐fold in static and 53.5‐fold in dynamic cultures, which was in good agreement with our model estimations (37‐fold increase in the number of cells in static and 49‐fold increase in dynamic cultures). In conclusion, our mathematical model could predict cell distribution and growth in the scaffold.     

Unmasking Heavily O-Glycosylated Serum Proteins Using Perchloric Acid: Identification of Serum Proteoglycan 4 and Protease C1 Inhibitor as Molecular Indicators for Screening of Breast Cancer

Heavily glycosylated mucin glycopeptides such as CA 27.29 and CA 15–3 are currently being used as biomarkers for detection and monitoring of breast cancer. However, they are not well detected at the early stages of the cancer. In the present study, perchloric acid (PCA) was used to enhance detection of mucin-type O-glycosylated proteins in the serum in an attempt to identify new biomarkers for early stage breast cancer. Sensitivity and specificity of an earlier developed sandwich enzyme-linked lectin assay were significantly improved with the use of serum PCA isolates. When a pilot case-control study was performed using the serum PCA isolates of normal participants (n = 105) and patients with stage 0 (n = 31) and stage I (n = 48) breast cancer, higher levels of total O-glycosylated proteins in sera of both groups of early stage breast cancer patients compared to the normal control women were demonstrated. Further analysis by gel-based proteomics detected significant inverse altered abundance of proteoglycan 4 and plasma protease C1 inhibitor in both the early stages of breast cancer patients compared to the controls. Our data suggests that the ratio of serum proteoglycan 4 to protease C1 inhibitor may be used for screening of early breast cancer although this requires further validation in clinically representative populations.     

Design and characterization of electrochemical dopamine–aptamer as convenient and integrated sensing platform

Here, an ultrasensitive label-free electrochemical aptasensor was developed for dopamine (DA) detection. Construction of the aptasensor was carried out by electrodeposition of gold–platinum nanoparticles (Au–PtNPs) on glassy carbon (GC) electrode modified with acid-oxidized carbon nanotubes (CNTs–COOH). A designed complementary amine-capped capture probe (ssDNA1) was immobilized at the surface of PtNPs/CNTs–COOH/GC electrode through the covalent amide bonds formed by the carboxyl groups on the nanotubes and the amino groups on the oligonucleotides. DA-specific aptamer was attached onto the electrode surface through hybridization with the ssDNA1. Methylene blue (MB) was used as an electrochemical indicator that was intercalated into the aptamer through the specific interaction with its guanine bases. In the presence of DA, the interaction between aptamer and DA displaced the MB from the electrode surface, rendering a lowered electrochemical signal attributed to a decreased amount of adsorbed MB. This phenomenon can be applied for DA detection. The peak current of probe (MB) linearly decreased over a DA concentration range of 1–30 nM with a detection limit of 0.22 nM.     

Proteomic analysis of sensitive and multi drug resistant <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> strains

Multidrug-resistant tuberculosis (MDR-TB) is caused by bacteria that are resistant to the most effective anti TB drugs (Isoniazid and Rifampicin) with or without resistance to other drugs. Novel intervention strategies to eliminate this disease based on finding proteins can be used for designing new drugs or new and reliable kits for diagnosis. The aim of this study was to compare the protein profile of MDR-TB with sensitive isolates. Two-dimensional gel electrophoresis (2DE) along with mass spectrometry is a powerful and effective tool to identification and characterization of Mycobacterium tuberculosis. Two-dimensional gel electrophoresis and matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry was used for diagnosis and comparison of proteins. We identified 14 protein spots in MDR-TB isolates that 2DE analysis showed these spots absent in M. tuberculosis sensitive isolates (Rv1876, Rv0379, Rv0147, Rv2031c, Rv3597c, Rv1886c, MT0493, Rv0440, Rv3614c, Rv1626, Rv0443, Rv0475, Rv3057 and unknown protein. The results showed 22 protein spots which were up regulated (or expressed) by the MDR-TB isolates, (Rv1240, Rv3028c, Rv2971, Rv2114c, Rv3311, Rv3699, Rv1023, Rv1308, Rv3774, Rv0831c, Rv2890c, Rv1392, Rv0719, Rv0054, Rv3418c, Rv0462, Rv2215, Rv2986c, Rv3248c and Rv1908c)). Two up regulated protein spots were identified in sensitive isolate (Rv1133c and Rv0685). These data will provide valuable clues in further investigation for suitable TB rapid tests or drug targets against drug resistant and sensitive of M. tuberculosis.     

Identification and inhibition of carbonic anhydrases from nematodes

Abstract

Carbonic anhydrases (CAs) are metalloenzymes, and classified into the evolutionarily distinct α, β, γ, δ, ζ, and η classes. α-CAs are present in many living organisms. β- and γ-CAs are expressed in most prokaryotes and eukaryotes, except for vertebrates. δ- and ζ-CAs are present in phytoplanktons, and η-CAs have been found in Plasmodium spp. Since the identification of α- and β-CAs in Caenorhabditis elegans, the nematode CAs have been considered as an emerging target in research focused on antiparasitic CA inhibitors. Despite the presence of α-CAs in both helminths and vertebrates, structural studies have revealed different kinetic and inhibition results. Moreover, lack of β-CAs in vertebrates makes this enzyme as an attractive target for inhibitory studies against helminthic infection. Some CA inhibitors, such as sulfonamides, have been evaluated against nematode CAs. This review article aims to present comprehensive information about the nematode CAs and their inhibitors as potential anthelminthic drugs.     

NPR3 protects cardiomyocytes from apoptosis through inhibition of cytosolic BRCA1 and TNF-α

Natriuretic peptide receptor 3 (NPR3) is a clearance receptor by binding and internalizing natriuretic peptides (NPs) for ultimate degradation. Patients with cardiac failure show elevated NPs. NPs are linked to poor long-term survival because of their apoptotic effects. However, the underling mechanisms have not been identified yet. Here we report the role of NPR3 in anti-apoptosis via the breast cancer type 1 susceptibility protein (BRCA1) and tumor necrosis factor α (TNF-α ). To demonstrate a role for NPR3 in apoptosis, stable H9C2 cardiomyocyte cell lines using shRNA to knockdown NPR3 were generated. The activities of caspase-3, 8, and 9 were significantly increased in NPR3 knockdown H9C2 cardiomyocytes. Knockdown of NPR3 increased the expression of BRCA1. Also NPR3 knockdown remarkably increased the activity of cAMP response element-binding protein (CREB), a positive regulatory element for BRCA1 expression. BRCA1 showed dispersed nuclear localization in non-cardiomyocytes while predominantly cytoplasmic localization in H9C2 cells. Meanwhile, NPR3 knockdown significantly increased TNF-α gene expression. These data show that NPR3 knockdown in H9C2 cells triggered both extrinsic and intrinsic apoptotic pathways. NPR3 protects cardiomyocytes from apoptosis through inhibition of cytosolic BRCA1 and TNF-α, which are regulators of apoptosis. Our studies demonstrate anti-apoptosis role of NPR3 in protecting cardiomyocytes and establish the first molecular link between NP system and programmed cell death.