UDP-Gal: <Emphasis Type="Italic">N</Emphasis>-acetylglucosamine β 1–4 galactosyltransferase expressing live attenuated parasites as vaccine for visceral leishmaniasis

As compared to cutaneous leishmaniasis, vaccination against visceral leishmaniasis (VL) has received limited attention. In this study, we demonstrate for the first time that an UDP-Galactose: N-acetylglucosamine β 1–4 galactosyltransferase (GenBank Accession No. EF159943) expressing attenuated LD clonal population (A-LD) is able to confer protection against the experimental challenge with the virulent LD AG83 parasite. A-LD was also effective in established leishmania infection. The vaccinated animals showed both cell mediated (in vitro T-cell proliferation, and DTH response) and humoral responses (Th1 type). These results demonstrate the potential of the attenuated clones as an immunotherapeutic and immunoprophylactic agent against visceral leishmaniasis.     

NMR characterisation of a triple stranded complex formed by homo-purine and homo-pyrimidine DNA strands at 1:1 molar ratio and acidic pH.

Homo-purine (d-TGAGGAAAGAAGGT) and homo-pyrimidine (d-CTCCTTTCTTCC) oligomers have been designed such that they are complementary in parallel orientation. When mixed in a 1:1 molar ratio, the system adopts an antiparallel duplex at neutral pH with three mismatched base pairs. On lowering the pH below 5.5, a new complex is formed. The NMR results show the coexistence of a intermolecular pyrimidine.purine:pyrimidine DNA triplex and a single stranded oligopurine at this pH. The triplex is stabilized by five T.A:T, four C+.G:C and two mismatched triads, namely, C+.G-T and T.A-C. This triplex is further stabilized by a Hoogsteen C+.G base-pair on one end. Temperature dependence of the imino proton resonances reveals that the triplex dissociates directly into single strands around 55 degrees C, without duplex intermediates. Parallel duplexes are not formed under any of the conditions employed in this study.     

Fluorescent multiplexing of 3D spheroids: Analysis of biomarkers using automated immunohistochemistry staining platform and multispectral imaging

In preclinical cancer studies, three-dimensional (3D) cell spheroids and aggregates are preferred over monolayer cell cultures due to their architectural and functional similarity to solid tumors. We performed a proof-of-concept study to generate physiologically relevant and predictive preclinical models using non–small cell lung adenocarcinoma, and colon and colorectal adenocarcinoma cell line-derived 3D spheroids and aggregates. Distinct panels were designed to determine the expression profiles of frequently studied biomarkers of the two cancer subtypes. The lung adenocarcinoma panel included ALK, EGFR, TTF-1, and CK7 biomarkers, and the colon and colorectal adenocarcinoma panel included BRAF V600E, MSH2, MSH6, and CK20. Recent advances in immunofluorescence (IF) multiplexing and imaging technology enable simultaneous detection and quantification of multiple biomarkers on a single slide. In this study, we performed IF staining of multiple biomarkers per section on formalin-fixed paraffin-embedded 3D spheroids and aggregates. We optimized protocol parameters for automated IF and demonstrated staining concordance with automated chromogenic immunohistochemistry performed with validated protocols. Next, post-acquisition spectral unmixing of the captured fluorescent signals were utilized to delineate four differently stained biomarkers within a single multiplex IF image, followed by automated quantification of the expressed markers. This workflow has the potential to be adapted to preclinical high-throughput screening and drug efficacy studies utilizing 3D spheroids from cancer cell lines and patient-derived organoids. The process allows for cost, time, and resource savings through concurrent staining of several biomarkers on a single slide, the ability to study the interactions of multiple expressed proteins within a single region of interest, and enable quantitative assessment of biomarkers in cancer cells.     

PIP3 but not PIP2 increases GLUT4 surface expression and glucose metabolism mediated by AKT/PKCζ/λ phosphorylation in 3T3L1 adipocytes

Phosphatidylinositol-3,4,5-triphosphate (PIP3) and phosphatidylinositol-4,5-biphosphate (PIP2) are two well-known membrane bound polyphosphoinositides. Diabetes is associated with impaired glucose metabolism. Using a 3T3L1 adipocyte cell model, this study investigated the role of PIP3 and PIP2 on insulin stimulated glucose metabolism in high glucose (HG) treated cells. Exogenous PIP3 supplementation (1, 5, or 10 nM) increased the phosphorylation of AKT and PKCζ/λ, which in turn upregulated GLUT4 total protein expression as well as its surface expression, glucose uptake, and glucose utilization in cells exposed to HG (25 mM); however, PIP2 had no effect. Comparative signal silencing studies with antisense AKT2 and antisense PKCζ revealed that phosphorylation of PKCζ/λ is more effective in PIP3 mediated GLUT4 activation and glucose utilization than in AKT phosphorylation. Supplementation with PIP3 in combination with insulin enhanced glucose uptake and glucose utilization compared to PIP2 with insulin, or insulin alone, in HG-treated adipocytes. This suggests that a decrease in cellular PIP3 levels may cause impaired insulin sensitivity in diabetes. PIP3 supplementation also prevented HG-induced MCP-1 and resistin secretion and lowered adiponectin levels. This study for the first time demonstrates that PIP3 but not PIP2 plays an important role in GLUT4 upregulation and glucose metabolism mediated by AKT/PKCζ/λ phosphorylation. Whether PIP3 levels in blood can be used as a biomarker of insulin resistance in diabetes needs further investigation.     

Self‐rescue of an EXTENSIN mutant reveals alternative gene expression programs and candidate proteins for new cell wall assembly in Arabidopsis

Plants encode a poorly understood superfamily of developmentally expressed cell wall hydroxyproline‐rich glycoproteins (HRGPs). One, EXTENSIN3 (EXT3) of the 168 putative HRGPs, is critical in the first steps of new wall assembly, demonstrated by broken and misplaced walls in its lethal homozygous mutant. Here we report the findings of phenotypic (not genotypic) revertants of the ext3 mutant and in‐depth analysis including microarray and qRT‐PCR (polymerase chain reaction). The aim was to identify EXT3 substitute(s), thus gaining a deeper understanding of new wall assembly. The data show differential expression in the ext3 mutant that included 61% (P ≤ 0.05) of the HRGP genes, and ability to self‐rescue by reprogramming expression. Independent revertants had reproducible expression networks, largely heritable over the four generations tested, with some genes displaying transgenerational drift towards wild‐type expression levels. Genes for nine candidate regulatory proteins as well as eight candidate HRGP building materials and/or facilitators of new wall assembly or maintenance, in the (near) absence of EXT3 expression, were identified. Seven of the HRGP fit the current model of EXT function. In conclusion, the data on phenotype comparisons and on differential expression of the genes‐of‐focus provide strong evidence that different combinations of HRGPs regulated by alternative gene expression networks, can make functioning cell walls, resulting in (apparently) normal plant growth and development. More broadly, this has implications for interpreting the cause of any mutant phenotype, assigning gene function, and genetically modifying plants for utilitarian purposes.     

Prevalence and Association of Mycobacterium avium subspecies paratuberculosis with Disease Course in Patients with Ulcero-Constrictive Ileocolonic Disease

Background

Association of Mycobacterium avium subspecies paratuberculosis (MAP) and Crohn’s disease (CD) has been controversial due to contradictory reports. Therefore, we determined the prevalence of MAP in patients with CD and intestinal tuberculosis (ITB) and its association with clinical course.

Methodology

Blood and intestinal biopsies were taken from 69 CD, 32 ITB patients and 41 patients with haemorrhoidal bleed who served as controls. qPCR targeting of MAP-specific IS900 gene was used to detect the presence of MAP DNA. qPCR results were further validated by sequencing. Immunohistochemistry (IHC) was used to detect the presence of MAP antigen in biopsy specimens. CD and ITB patients were followed-up for disease course and response to therapy.

Principal Findings

The frequency of MAP-specific DNA in biopsies by qPCR was significantly higher in CD patients (23.2%, p = 0.03) as compared to controls (7.3%). No significant difference in intestinal MAP presence was observed between ITB patients (12.5%, p = 0.6) and controls (7.3%). MAP presence in blood of CD patients was 10.1% as compared to 4.9% in controls while no patients with ITB were found to be positive (p = 0.1). Using IHC for detection of MAP antigen, the prevalence of MAP in CD was 2.9%, 12.5% in ITB patients and 2.4% in controls. However, long-term follow-up of the patients revealed no significant associations between clinical characteristics and treatment outcomes with MAP positivity.

Conclusion

We report significantly high prevalence of MAP in intestinal biopsies of CD patients. However, the presence of MAP does not affect the disease course and treatment outcomes in either CD or ITB patients.