CD56bright cells respond to stimulation until very advanced age revealing increased expression of cellular protective proteins SIRT1, HSP70 and SOD2

Background

NK cells are cytotoxic lymphocytes of innate immunity composed of: cytotoxic CD56dim and immunoregulatory CD56bright cells. The study aimed to analyze the expression of cellular protective proteins: sirtuin 1 (SIRT1), heat shock protein 70 (HSP70) and manganese superoxide dismutase (SOD2) in CD56dim and CD56bright NK cells of the young, seniors aged under 85 (‘the old’) and seniors aged over 85 (‘the oldest’). We studied both non-stimulated NK cells and cells stimulated by IL-2, LPS or PMA with ionomycin. The expression level of proinflammatory cytokines TNF and IFN-γ was also assessed in NK cell subsets and some relationships between the studied parameters were analyzed.

Results

CD56bright cells showed sensitivity to most of the applied stimulatory agents until very advanced age in regards to the expression of SIRT1 and intracellular HSP70. On the contrary, CD56dim cells, sensitive to stimulation by most of the stimulatory agents in the young and the old, in the oldest lost this sensitivity and presented rather high, constant expression of SIRT1 and HSP70, resistant to further stimulation. With reference to SOD2 expression, CD56dim cells were insensitive to stimulation in the young, but their sensitivity increased with ageing. CD56bright cells were sensitive to most of the applied agents in the young and the old but in the oldest they responded to all of the stimulatory agents used in the study. Similarly, both NK cell subsets were sensitive to stimulation until very advanced age in regards to the expression of TNF and IFN-γ.

Conclusions

CD56bright cells maintained sensitivity to stimulation until very advanced age presenting also an increased expression of SIRT1 and HSP70. CD56dim cells showed a constantly increased expression of these cellular protective proteins in the oldest, insensitive for further stimulation. The oldest, however, did not reveal an increased level of SOD2 expression, but it was significantly elevated in both NK cell subsets after stimulation.The pattern of expression of the studied cellular protective proteins in ageing process revealed the adaptation of NK cells to stress response in the oldest seniors which might accompany the immunosenescence and contribute to the long lifespan of this group of the elderly.

     

<Emphasis Type="Italic">ABI3</Emphasis> and <Emphasis Type="Italic">PLCG2</Emphasis> missense variants as risk factors for neurodegenerative diseases in Caucasians and African Americans

Background

Rare coding variants ABI3_rs616338-T and PLCG2_rs72824905-G were identified as risk or protective factors, respectively, for Alzheimer’s disease (AD).

Methods

We tested the association of these variants with five neurodegenerative diseases in Caucasian case-control cohorts: 2742 AD, 231 progressive supranuclear palsy (PSP), 838 Parkinson’s disease (PD), 306 dementia with Lewy bodies (DLB) and 150 multiple system atrophy (MSA) vs. 3351 controls; and in an African-American AD case-control cohort (181 AD, 331 controls). 1479 AD and 1491 controls were non-overlapping with a prior report.

Results

Using Fisher’s exact test, there was significant association of both ABI3_rs616338-T (OR?=?1.41, p?=?0.044) and PLCG2_rs72824905-G (OR?=?0.56, p?=?0.008) with AD. These OR estimates were maintained in the non-overlapping replication AD-control analysis, albeit at reduced significance (ABI3_rs616338-T OR?=?1.44, p?=?0.12; PLCG2_rs72824905-G OR?=?0.66, p?=?0.19). None of the other cohorts showed significant associations that were concordant with those for AD, although the DLB cohort had suggestive findings (Fisher’s test: ABI3_rs616338-T OR?=?1.79, p?=?0.097; PLCG2_rs72824905-G OR?=?0.32, p?=?0.124). PLCG2_rs72824905-G showed suggestive association with pathologically-confirmed MSA (OR?=?2.39, p?=?0.050) and PSP (OR?=?1.97, p?=?0.061), although in the opposite direction of that for AD. We assessed RNA sequencing data from 238 temporal cortex (TCX) and 224 cerebellum (CER) samples from AD, PSP and control patients and identified co-expression networks, enriched in microglial genes and immune response GO terms, and which harbor PLCG2 and/or ABI3. These networks had higher expression in AD, but not in PSP TCX, compared to controls. This expression association did not survive adjustment for brain cell type population changes.

Conclusions

We validated the associations previously reported with ABI3_rs616338-T and PLCG2_rs72824905-G in a Caucasian AD case-control cohort, and observed a similar direction of effect in DLB. Conversely, PLCG2_rs72824905-G showed suggestive associations with PSP and MSA in the opposite direction. We identified microglial gene-enriched co-expression networks with significantly higher levels in AD TCX, but not in PSP, a primary tauopathy. This co-expression network association appears to be driven by microglial cell population changes in a brain region affected by AD pathology. Although these findings require replication in larger cohorts, they suggest distinct effects of the microglial genes, ABI3 and PLCG2 in neurodegenerative diseases that harbor significant vs. low/no amyloid ß pathology.

     

High‐performance liquid chromatographic enantioseparation of N‐aryl‐thioureidoalkylphosphonates and thiourylenedi(alkylphosphonates) on polysaccharide‐based chiral stationary phases

The first successful enantioseparation of representative O,O‐diphenyl‐N‐arylthioureidoalkylphosphonates, (±)‐Ptc‐Val^P(OPh)₂ & (±)‐Ptc‐Leu^P(OPh)₂ and thiourylenedi(isobutyl phosphonate), Tcm[Val^P(OPh)₂]₂ on analytical and semipreparative scale was achieved by high‐performance liquid chromatography using polysaccharide‐based chiral stationary phases (CPs). Atc‐AA^P(OPh)₂ was obtained using modified tricomponent condensations of the corresponding aldehydes, N‐arylthiourea and triphenyl phosphite whereas Tcm[Val^P(OPh)₂]₂ by the condensations of aldehydes, thiourea, and triphenyl phosphite. The prepared, racemic (±)‐Atc‐AA^P(OPh)₂ [(±)‐Ptc‐Val^P(OPh)₂, (±)‐Ptc‐Leu^P(OPh)₂, (±)‐Ptc‐Pgly^P(OPh)₂ and (±)‐Ntc‐Pgly^P(OPh)₂] and racemic (±)‐Tcm[AA^P(OPh)₂]₂ [(±)‐Tcm[Nva^P(OPh)₂]₂ & (±)‐Tcm[Val^P(OPh)₂]₂] were adequately characterized and used for chromatographic separations on high‐performance liquid chromatography–chiral stationary phases. The best results were obtained for (±)‐Ptc‐Val^P(OPh)₂, (±)‐Ptc‐Leu^P(OPh)₂ and (±)‐Tcm[Val^P(OPh)₂]₂.     

Triterpene saponosides from Lysimachia ciliata differentially attenuate invasive potential of prostate cancer cells

Neither androgen ablation nor chemotherapeutic agents are effective in reducing the risk of prostate cancer progression. On the other hand, multifaceted effects of phytochemicals, such as triterpene saponins, on cancer cells have been suggested. A promising safety and tolerability profile indicate their possible application in the treatment of advanced prostate cancers. We analyzed the specificity, selectivity and versatility of desglucoanagalloside B effects on human prostate cancer cells derived from prostate cancer metastases to brain (DU-145 cells) and bone (PC-3 cells). Prominent growth arrest and apoptotic response of both cell types was observed in the presence of sub-micromolar desglucoanagalloside B concentrations. This was accompanied by cytochrome c release and caspase 3/7 activation. A relatively low cytostatic and pro-apoptotic response of cancer cells to a desglucoanagalloside B analog, anagallosaponin IV, illustrated the specificity of the effects of desglucoanagalloside B, whereas the low sensitivity of normal prostate PNT2 cells to desglucoanagalloside B showed the selectivity of its action. Inhibition of cancer cell motility was observed in the presence of both saponins, however only desglucoanagalloside B attenuated cancer cell invasive potential, predominantly through an effect on cell elastic properties. These data demonstrate the versatility of its effects on prostate cancer cells. In contrast to PNT2 cells, cancer cells tested in this study were relatively resistant to mitoxantrone. The multifaceted action of desglucoanagalloside B on basic cellular traits, crucial for prostate cancer progression, opens perspectives for elaboration of combined palliative therapies and new prostate cancer prophylaxis regimens.     

Potential Regulatory Interactions of Escherichia coli RraA Protein with DEAD-box Helicases

Members of the DEAD-box family of RNA helicases contribute to virtually every aspect of RNA metabolism, in organisms from all domains of life. Many of these helicases are constituents of multicomponent assemblies, and their interactions with partner proteins within the complexes underpin their activities and biological function. In Escherichia coli the DEAD-box helicase RhlB is a component of the multienzyme RNA degradosome assembly, and its interaction with the core ribonuclease RNase E boosts the ATP-dependent activity of the helicase. Earlier studies have identified the regulator of ribonuclease activity A (RraA) as a potential interaction partner of both RNase E and RhlB. We present structural and biochemical evidence showing how RraA can bind to, and modulate the activity of RhlB and another E. coli DEAD-box enzyme, SrmB. Crystallographic structures are presented of RraA in complex with a portion of the natively unstructured C-terminal tail of RhlB at 2.8-Å resolution, and in complex with the C-terminal RecA-like domain of SrmB at 2.9 Å. The models suggest two distinct mechanisms by which RraA might modulate the activity of these and potentially other helicases.     

Phosphorylation of Nucleoside-Metallacarborane and Carborane Conjugates by Nucleoside Kinases

A library of purine and pyrimidine nucleosides modified with carborane or metallacarborane boron clusters at different locations, consisting of new molecules as well as already described compounds, was prepared. The compounds were tested as substrates for human deoxynucleoside kinases. Some conjugates, with modification attached to N3 of thymidine via a linker containing the triazole moiety, were efficiently phosphorylated by cytosolic thymidine kinase 1 and mitochondrial thymidine kinase 2. Higher phosphorylation levels were observed with thymidine kinase 1, the phosphorylation of nucleosides modified with metallacarboranes was observed for the first time.     

The influence of environmental factors on the rate and extent of stainless steel ennoblement mediated by manganese‐oxidizing biofilms

The increase in the open circuit potential of passive metals in natural waters due to biofilm formation at the metal surface, termed ennoblement, has been reported for nearly 30 years. Although its occurrence is undoubtedly associated with microbial colonization, the underlying mechanism of ennoblement remains controversial. Recent work produced in the authors’ laboratory has provided convincing experimental evidence that ennoblement can be caused by deposition of biomineralized manganese produced by manganese‐oxidizing biofilms. The purpose of this study was to determine the effects of environmental factors on the rate and extent of ennoblement of 316L stainless steel exposed to natural waters. This was accomplished by exposing corrosion coupons to four freshwater systems over a 4‐yearperiod. The rate and extent of ennoblement observed in these locations was correlated with dissolved manganese concentrations, the mass of accumulated manganese oxides, organic carbon concentration, dissolved oxygen concentration, flow, conditions, temperature, and pH in these environments.     

Resistance of biofilms containing alginate‐producing bacteria to disintegration by an alginate degrading enzyme (Algl)

Pure culture biofilms of Pseudomonas aeruginosa (strains 8830 and ATCC 700829) and mixed population biofilms composed of Pseudomonas aeruginosa (ATCC 700829), Pseudomonas fluorescens (ATCC 700830), and Klebsiellapneumoniae (ATCC 700831) were treated with an alginate‐degrading enzyme (AlgL). The enzyme effectively depolymerized the mannuronic acid rich (92%), partially O‐acetylated bacterial alginate produced by P. aeruginosa (8830), both in dilute solution and in a gel‐like, concentrated state. However, both biofilms were unaffected by the presence of the enzyme. These findings suggest either that bacterial alginates do not contribute significantly to the cohesiveness of biofilms or that the alginate is protected from enzymatic degradation in biofilms.