Low Molecular Weight Form Research Articles

The beneficial impact of kosmotropic salts on the resolution and selectivity of Protein A chromatography

During the manufacturing of therapeutic antibodies, effective Protein A chromatography as initial column step is crucial to simplify the remaining purification effort for subsequent polishing steps. This is particularly relevant for molecules with high impurity content so that desired product purity can be attained. The present study demonstrates beneficial effects on impurity removal when applying kosmotropic salts, e.g., sodium sulfate or sodium chloride, in the elution phase. Initially, a screen using negative linear pH gradient elution evaluated the impact of the kosmotropic salts in comparison to no additive and chaotropic urea using three mAbs and three common resins. Retaining acceptable yield, the kosmotropic salts improved resolution of monomer and impurities and reduced the contents of process-related host cell proteins and DNA as well as of product-related low and high molecular weight forms, despite some resin- and mAb-dependent variations. Moreover, a decrease in hydrolytic activity measured by a new assay for polysorbase activity was observed. In contrast, urea was hardly effective. The findings served to establish optimized step elution conditions with 0.25 M of sodium sulfate for a challenging mAb with complex format (bispecific 2 + 1 CrossMab) displaying high relative hydrophobicity and impurity levels. With yield and purity both in the range of 90 %, the contents of all impurity components were reduced, e.g., low molecular weight forms by two-fold and polysorbase activity by four-fold. The study indicates the potential of kosmotropic salts to establish efficient and comprehensive impurity separation by Protein A for facilitated downstream processing and economic manufacturing of complex antibodies.

Extracellular high molecular weight α-synuclein oligomers induce cell death by disrupting the plasma membrane

α-Synuclein (αS), the causative protein of Parkinson’s disease and other α-synucleinopathies, aggregates from a low molecular weight form (LMW-αS) to a high molecular weight αS oligomer (HMW-αSo). Aggregated αS accumulates intracellularly, induces intrinsic apoptosis, is released extracellularly, and appears to propagate disease through prion-like spreading. Whether extracellular αS aggregates are cytotoxic, damage cell wall, or induce cell death is unclear. We investigated cytotoxicity and cell death caused by HMW-αSo or LMW-αS. Extracellular HMW-αSo was more cytotoxic than LMW-αS and was a crucial factor for inducing plasma membrane damage and cell death. HMW-αSo induced reactive oxygen species production and phospholipid peroxidation in the membrane, thereby impairing calcium homeostasis and disrupting plasma membrane integrity. HMW-αSo also induced extrinsic apoptosis and cell death by activating acidic sphingomyelinase. Thus, as extracellular HMW-αSo causes neuronal injury and death via cellular transmission and direct plasma membrane damage, we propose an additional disease progression pathway for α-synucleinopathies.

Potential targets of heparin during progression and metastasis of malignant neoplasms

In the modern world, oncological diseases occupy the leading positions in the structure of mortality. An integrated approach to oncotherapy is not only aimed at immediate affection of malignant tumors, but also directed at reducing the risk of tumor recurrence and metastasis, as well as alleviating side effects of chemotherapy and radiotherapy of the disease. In oncologic disorders, blood viscosity increases, thus being associated with hypercoagulation syndrome. To prevent its consequences, the direct and indirect anticoagulants, especially heparin and its derivatives, are actively used. Biological functions and structural features of heparin make it a potential universal platform of a drug development for broad application, including oncology. With the advent of heparin fractionation technology and preparation of low-molecular weight forms and their derivatives, it has become possible to focus not only on anticoagulant activity but also to obtain fractions with targeted pharmacological activity. Usage of the anticoagulants has shown their antitumor activity in some cases, thus providing a basis for a more detailed study of pharmacotherapeutic effects of this group of drugs. Currently, some data suggest various pathways of interaction between heparin and tumor cells. There are multiple common features in development of a primary tumor and formation of secondary distant metastases, which may be attributed to similar molecular cellular mechanisms. The molecules mediating intercellular interactions, both between the tumor cells and between malignant cells and tumor-associated immune cells (e.g., lymphocytes and macrophages) may serve as targets for heparin thus helping the tumor to evade immune surveillance. The cytokines that stimulate tumor angiogenesis represent another important therapeutic target. Heparin derivatives are able to suppress tumor activity and prevent metastatic processes at various stages by inhibiting heparanase, P-/L-selectin, and angiogenesis activity, modulating the CXCL12-CXCR4 chemokine axis, and regulating OAM activity.This brief review addresses the current understanding and application of the potentially antimetastatic properties of heparin and its derivatives in malignant bone tumors since the heparin-based drugs are used as anticoagulants in arthroplasty of large joints and bone defects in patients with osteosarcoma.

Functional changes of OsTrxm from reductase to molecular chaperone under heat shock stress

Ubiquitous disulfide reductases, thioredoxins (Trxs), function in the redox balance of all living organisms. Although the roles of the rice (Oryza sativa) Trx m-type isoform (OsTrxm) in chloroplast development have been already published, biochemical and molecular functions of OsTrxm remain to be elucidated for decades. The OsTrxm and its two conserved active cysteine mutant (OsTrxm C95S/C98S, referred to as OsTrxmC/S) proteins in Arabidopsis thaliana were overexpressed to characterize in vivo roles of active cysteines of OsTrxm. Interestingly, the OsTrxm overexpressed variant plants were resistant to heat shock treatment. Especially OsTrxmC/S with higher molecular weight (HMW) complexes showed higher heat tolerance than OsTrxm with lower molecular weight (LMW) structure in Arabidopsis thaliana. To confirm the importance of active cysteines on structural changes under heat stress, OsTrxm and OsTrxmC/S proteins were bacterially expressed and isolated. This study found that two proteins have various structures ranging from LMW to HMW complexes and have potential functions as a disulfide reductase and a molecular chaperone, which has never been reported anywhere. The function of molecular chaperone predominated in the HMW complexes, whereas the disulfide reductase function was observed in LMW forms. These results suggest that the active cysteines of OsTrxm play a critical role in protein structural change as well as heat tolerance in plants.

A Model of iPSC-Derived Macrophages with TNFAIP3 Overexpression Reveals the Peculiarities of TNFAIP3 Protein Expression and Function in Human Macrophages.

Macrophages play a crucial role in the development and control of inflammation. Understanding the mechanisms balancing macrophage inflammatory activity is important to develop new strategies for treating inflammation-related diseases. TNF-α-induced protein 3 (TNFAIP3, A20) is a negative regulator of intracellular inflammatory cascades; its deficiency induces hyper-inflammatory reactions. Whether A20 overexpression can dampen macrophage inflammatory response remains unclear. Here, we generated human-induced pluripotent stem cells with tetracycline-inducible A20 expression and differentiated them into macrophages (A20-iMacs). A20-iMacs displayed morphology, phenotype, and phagocytic activity typical of macrophages, and they displayed upregulated A20 expression in response to doxycycline. A20 overexpression dampened the A20-iMac response to TNF-α, as shown by a decreased expression of IL1B and IL6 mRNA. A dynamic analysis of A20 expression following the generation of A20-iMacs and control iMacs showed that the expression declined in iMacs and that iMacs expressed a lower molecular weight form of the A20 protein (~70 kDa) compared with less differentiated cells (~90 kDa). A low-level expression of A20 and the predominance of a low-molecular-weight A20 form were also characteristic of monocyte-derived macrophages. The study for the first time developed a model for generating macrophages with an inducible expression of a target gene and identified the peculiarities of A20 expression in macrophages that likely underlie macrophage preparedness for inflammatory reactivity. It also suggested the possibility of mitigating inflammatory macrophage responses via A20 overexpression.

Matrix metalloproteinases in oral cancer: A catabolic activity on extracellular matrix components

Zinc-dependent proteolytic enzymes known as matrix metalloproteinases (MMPs) are a class of structurally related enzymes that are known to be crucial in the catabolic turnover of extracellular matrix (ECM) components. MMPs are thought to control the activity of a number of non-ECM bioactive substrates, such as growth factors, cytokines, chemokines, and cell receptors, which control the tissue microenvironment. The interaction between cells and ECM plays a key role in normal development and differentiation of organism and many pathological states as well. The primary class of controlling proteases in the ECM is known as MMPs. Aspects of normal physiology and pathology depend on the ability of MMPs to change the structural integrity of tissues. Uncontrolled ECM turnover, tissue remodeling, inflammatory response, cell proliferation, and migration are pathogenic alterations that can result from an imbalance between the concentration of active metalloproteinases and their inhibitors (tissue inhibitors of metalloproteinases [TIMPs]). This detailed review provides some information on the function of MMPs in inflammatory, caries and periapical, cancer, and other oral diseases. Blood and saliva are the two biological fluids that are most frequently used to diagnose oral disorders. Most of the ECM components in patients undergo digestion to lower molecular weight forms, resulting in much higher amounts of MMPs in their saliva/blood than in healthy individuals. Conventional treatment successfully reduces the levels of MMPs which inhibits the progressive breakdown of collagens in ECM components.

1107 PLASMA CIRCULATING TRANSTHYRETIN FORMS IN PATIENTS WITH WILD TYPE TRANSTHYRETIN CARDIAC AMYLOIDOSIS

Abstract Background and aims Wild type transthyretin (TTR) cardiac amyloidosis (ATTRwt-CA) is caused by the misfolding, aggregation and tissue deposition of native TTR, leading to cardiac structural remodeling. In the last decade, the validation of non-invasive diagnostic approaches and the development of novel therapeutic options targeting the amyloidogenic cascade, such as the TTR stabilizer tafamidis, have dramatically changed the epidemiology and the prognosis of the disease. Nonetheless, the basic pathophysiological mechanisms underlying TTR misfolding and aggregation are still poorly understood. We aimed to characterize circulating TTR forms in plasma samples of ATTRwt-CA patients before and after treatment with tafamidis through a native electrophoretic method. Methods Plasma samples from 6 male patients with ATTRwt amyloidosis (median age 82 years, IQR 80-83), collected before (T0) and during tafamidis treatment, and from 6 healthy controls were collected. Plasma samples were separated on a native 4–20% Tris-Gly polyacrylamide gel. Western blot analysis was performed with anti-TTR or anti-retinol-binding protein (RBP) antibodies. Proteins were detected by Clarity ECL substrate. Results Circulating TTR forms were qualitatively similar between ATTRwt-CA patients at T0 and controls. In both groups, the most represented forms were TTR dimers or trimers (∼37-50 kDa), TTR tetramers complexed with RBP in 1:1 ratio (∼80 kDa) or 1:2 ratio (∼100 kDa), and high molecular weight (MW) aggregates (>150 kDa). Neither TTR monomers nor tetramers could be detected. RBP protein was detectable in association with TTR tetramers and some of the higher MW fractions (∼150 kDa, >250 kDa). Following tafamidis treatment, all ATTRwt-CA patients displayed a progressive increase of the intensity of the band corresponding to TTR-RBP complexes, in agreement with the a stabilizing action on TTR tetramers. Interestingly, dimers and trimers, detectable at T0, were progressively lost during tafamidis treatment. Conclusions TTR tetramer exists only complexed with RBP and in equilibrium with low and high MW forms, without apparent qualitative differences between ATTR-CA and healthy controls. Tafamidis increases circulating TTR tetramers complexed with RBP. Evaluation of TTR isoform may prove useful as a circulating biomarker for the assessment of response to treatment in patients with ATTRwt-CA.

276 CIRCULATING FORMS OF PLASMA TRANSTHYRETIN IN PATIENTS WITH WILD-TYPE TRANSTHYRETIN AMYLOIDOSIS AND EFFECTS OF TREATMENT WITH TAFAMIDIS

Abstract Introduction Transthyretin (TTR) is a homotetrameric 55-KDa plasma protein that transports thyroxin and retinol complexed to retinol-binding protein (RBP). TTR misfolding and aggregation can lead to the extracellular deposition of amyloid (ATTR) representing one of the most frequent forms of amyloidosis in elderly. Aim of this study is to develop a native electrophoretic method to characterize circulating TTR in plasma samples of ATTR patients before and during treatment with tafamidis, a TTR stabilizer. Methods Plasma from ATTR patients (n=6), collected before (T0) and during tafamidis treatment, and plasma of healthy controls (n=6) were obtained from Fondazione Toscana G. Monasterio (Pisa, Italy). Plasma samples were separated on a native 4–20% Tris-Gly polyacrylamide gel. Western blot analysis was performed with anti-TTR (DAKO) or anti-RBP (Siemens Healthineer) antibodies. Proteins were detected by Clarity ECL substrate (BioRad). Results Circulating forms of TTR were qualitatively similar between ATTRwt patients at T0 and controls. In both groups, the most represented forms were: TTR dimers or trimers (∼37-50 kDa), TTR tetramers complexed with RBP protein in 1:1 ratio (∼80 kDa,) or 1:2 ratio (∼100 kDa), and high molecular weight (MW) aggregates (>150 kDa). Neither TTR monomers nor the tetramers were visible. RBP protein was detectable in association with TTR tetramers and some of the higher MW fractions (∼150 kDa, >250 kDa). Following tafamidis treatment, all ATTRwt patients displayed a progressive increase of the intensity of the band corresponding to TTR-RBP complexes, in agreement with the drug stabilizing action on TTR tetramers. Interestingly dimers and trimers, detectable at T0, were progressively lost during tafamidis treatment. Conclusions The native electrophoretic allowed us to detect several circulating TTR fractions. Data suggest a similar pattern of circulating TTR both in patients and healthy control: TTR tetramer exists only complexed with RBP and in equilibrium with low and high MW forms. Furthermore, the method allowed to appreciate the stabilizing effect of tafamidis on circulating TTR tetramers complexed with RBP. The study of circulating TTR fractions can expand our knowledge on mechanisms triggering its destabilization even when not mutated.

A Hybrid Structural Method for Investigating Low Molecular Weight Oligomeric Structures of Amyloid Beta.

Spurred in part by the failure of recent therapeutics targeting amyloid β plaques in Alzheimer's Disease (AD), attention is increasingly turning to the oligomeric forms of this peptide that form early in the aggregation process. However, while numerous amyloid β fibril structures have been characterized, primarily by NMR spectroscopy and cryo-EM, obtaining structural information on the low molecular weight forms of amyloid β that presumably precede and/or seed fibril formation has proved challenging. These transient forms are heterogeneous, and depend heavily on experimental conditions such as buffer, temperature, concentration, and degree of quiescence during measurement. Here, we present the concept for a new approach to delineating structural features of early-stage low molecular weight amyloid β oligomers, using a solvent accessibility assay in conjunction with simultaneous fluorescence measurements.

Functional Characterization of an Arabidopsis Profilin Protein as a Molecular Chaperone under Heat Shock Stress.

Profilins (PFNs) are actin monomer-binding proteins that function as antimicrobial agents in plant phloem sap. Although the roles of Arabidopsis thaliana profilin protein isoforms (AtPFNs) in regulating actin polymerization have already been described, their biochemical and molecular functions remain to be elucidated. Interestingly, a previous study indicated that AtPFN2 with high molecular weight (HMW) complexes showed lower antifungal activity than AtPFN1 with low molecular weight (LMW). These were bacterially expressed and purified to characterize the unknown functions of AtPFNs with different structures. In this study, we found that AtPFN1 and AtPFN2 proteins have LMW and HMW structures, respectively, but only AtPFN2 has a potential function as a molecular chaperone, which has never been reported elsewhere. AtPFN2 has better protein stability than AtPFN1 due to its higher molecular weight under heat shock conditions. The function of AtPFN2 as a holdase chaperone predominated in the HMW complexes, whereas the chaperone function of AtPFN1 was not observed in the LMW forms. These results suggest that AtPFN2 plays a critical role in plant tolerance by increasing hydrophobicity due to external heat stress.

Construction and Evaluation of Recombinant Chimeric Fibrillin and Elastin Fragment in Human Mesenchymal Stem Cells.

Diverse extracellular matrix (ECM) proteins physically interact with stem cells and regulate stem cell function. However, the large molecular weight of the natural ECM renders large-scale fabrication of a similar functional structure challenging. The objective of this study was to construct a low molecular weight and multifunctional chimeric form of recombinant ECM to stimulate mesenchymal stem cell (MSC) for tissue repair. We engineered Fibrillin-1PF14 fused to an elastin-like polypeptide to develop a new biomimetic ECM for stem cell differentiation and investigated whether this recombinant chimeric Fibrillin-Elastin fragment (rcFE) was effective on human nasal inferior turbinate-derived mesenchymal stem cells (hTMSCs). hTMSCs were grown in the medium supplemented with rcFE, then the effect of the protein was confirmed through cell adhesion assay, proliferation assay, and real-time PCR. rcFE enhanced the adhesion activity of hTMSCs by 2.7-fold at the optimal concentration, and the proliferation activity was 2.6-fold higher than that of the control group (non-treatment rcFE). In addition, when smooth muscle cell differentiation markers were identified by real-time PCR, Calponin increased about 6-fold, α-actin about 9-fold, and MYH11 about 10-fold compared to the control group. Chimeric rcFE enhanced cellular functions such as cell adhesion, proliferation, and smooth muscle differentiation of hTMSCs, suggesting that the rcFE can facilitate the induction of tissue regeneration.

Abstract NG09: Bioengineered tissue mimetic hydrogels to study brain tumor biology and screen therapeutics

Abstract NG09: Bioengineered tissue mimetic hydrogels to study brain tumor biology and screen therapeutics

Cleaved PINK1 induces neuronal plasticity through PKA-mediated BDNF functional regulation.

Mutations in PTEN-induced kinase 1 (PINK1) lead to early onset autosomal recessive Parkinson's disease in humans. In healthy neurons, full-length PINK1 (fPINK1) is post-translationally cleaved into different lower molecular weight forms, and cleaved PINK1 (cPINK1) gets shuttled to the cytosolic compartments to support extra-mitochondrial functions. While numerous studies have exemplified the role of mitochondrially localized PINK1 in modulating mitophagy in oxidatively stressed neurons, little is known regarding the physiological role of cPINK1 in healthy neurons. We have previously shown that cPINK1, but not fPINK1, modulates the neurite outgrowth and the maintenance of dendritic arbors by activating downstream protein kinase A (PKA) signaling in healthy neurons. However, the molecular mechanisms by which cPINK1 promotes neurite outgrowth remain to be elucidated. In this report, we show that cPINK1 supports neuronal development by modulating the expression and extracellular release of brain-derived neurotrophic factor (BDNF). Consistent with this role, we observed a progressive increase in the level of endogenous cPINK1 but not fPINK1 during prenatal and postnatal development of mouse brains and during development in primary cortical neurons. In cultured primary neurons, the pharmacological activation of endogenous PINK1 leads to enhanced downstream PKA activity, subsequent activation of the PKA-modulated transcription factor cAMP response element-binding protein (CREB), increased intracellular production and extracellular release of BDNF, and enhanced activation of the BDNF receptor-TRKβ. Mechanistically, cPINK1-mediated increased dendrite complexity requires the binding of extracellular BDNF to TRKβ. In summary, our data support a physiological role of cPINK1 in stimulating neuronal development by activating the PKA-CREB-BDNF signaling axis in a feedforward loop.

Genetic markers and phosphoprotein forms of beta-catenin pβ-Cat552 and pβ-Cat675 are prognostic biomarkers of cervical cancer.

BACKGROUNDCervical cancer (CC) remains a leading cause of gynaecological cancer-related mortality world wide and constitutes the third most common malignancy in women. The RAIDs consortium (http://www.raids-fp7.eu/) conducted a prospective European study [BioRAIDs (NCT02428842)] with the objective to stratify CC patients for innovative treatments. A “metagene” of genomic markers in the PI3K pathway and epigenetic regulators had been previously associated with poor outcome [2].METHODSTo detect new, more specific, targets for treatment of patients who resist standard chemo-radiation, a high-dimensional Cox model was applied to define dominant molecular variants, copy number variations, and reverse phase protein arrays (RPPA).FINDINGSSurvival analysis on 89 patients with all omics data available, suggested loss-of-function (LOF) or activating molecular alterations in nine genes to be candidate biomarkers for worse prognosis in patients treated by chemo-radiation while LOF of ATRX, MED13 as well as CASP8 were associated with better prognosis. When protein expression data by RPPA were factored in, the supposedly low molecular weight and nuclear form, of beta-catenin, phosphorylated in Ser552 (pβ-Cat552), ranked highest for good prognosis, while pβ-Cat675 was associated with worse prognosis.INTERPRETATIONThese findings call for molecularly targeted treatments involving p53, Wnt pathway, PI3K pathway, and epigenetic regulator genes. Pβ-Cat552 and pβ-Cat675 may be useful biomarkers to predict outcome to chemo-radiation, which targets the DNA repair axis.FUNDINGEuropean Union's Seventh Program for research, technological development and demonstration (agreement N°304,810), the Fondation ARC pour la recherche contre le cancer.

Development of fully automated and ultrasensitive assays for urinary adiponectin and their application as novel biomarkers for diabetic kidney disease

Glomerular filtration rate (GFR) and urinary albumin excretion rate (UAER) are used to diagnose and classify the severity of chronic kidney disease. Total adiponectin (T-AN) and high molecular weight adiponectin (H-AN) assays were developed using the fully automated immunoassay system, HI-1000 and their significance over conventional biomarkers were investigated. The T-AN and H-AN assays had high reproducibility, good linearity, and sufficient sensitivity to detect trace amounts of adiponectin in the urine. Urine samples after gel filtration were analyzed for the presence of different molecular isoforms. Low molecular weight (LMW) forms and monomers were the major components (93%) of adiponectin in the urine from a diabetic patient with normoalbuminuria. Urine from a microalbuminuria patient contained both high molecular weight (HMW) (11%) and middle molecular weight (MMW) (28%) adiponectin, although the LMW level was still high (52%). The amount of HMW (32%) and MMW (42%) were more abundant than that of LMW (24%) in a diabetic patient with macroalbuminuria. T-AN (r = − 0.43) and H-AN (r = − 0.38) levels showed higher correlation with estimated GFR (eGFR) than UAER (r = − 0.23). Urinary levels of both T-AN and H-AN negatively correlated with renal function in diabetic patients and they may serve as new biomarkers for diabetic kidney disease.

HSPA8 knock-down induces the accumulation of neurodegenerative disorder-associated proteins

Heat shock protein 70 family was demonstrated to play a critical role in protein homeostasis, a process profoundly impaired in neurodegenerative disorders. Neurodegenerative diseases are characterized by the accumulation of different kind of proteins and the formation of insoluble aggregates which are toxic for neurons. To explore the role of heat shock protein family 70 (in particular HSPA8 and HSPA1A) in the accumulation of proteins implied in neurodegeneration pathogenesis, in this study we verified in human SH-SY5Y neuroblastoma cells how HSPA8 or HSPA1A knock-down can affect protein levels of tau, superoxide dismutase 1 and α-synuclein. We found HSPA8 and HSPA1A reduction caused an increase of tau, superoxide dismutase 1 and α-synuclein protein levels. We also noticed HSPA8 knock-down increased α-synuclein oligomeric forms and mRNA expression. Our results suggest HSPA8 can play an important role in the homeostasis of tau, superoxide dismutase 1 and α-synuclein and in the balance between α-synuclein oligomeric and monomeric forms.

Streptococcus suis Uptakes Carbohydrate Source from Host Glycoproteins by N-glycans Degradation System for Optimal Survival and Full Virulence during Infection.

Infection with the epidemic virulent strain of Streptococcus suis serotype 2 (SS2) can cause septicemia in swine and humans, leading to pneumonia, meningitis and even cytokine storm of Streptococcal toxic shock-like syndrome. Despite some progress concerning the contribution of bacterial adhesion, biofilm, toxicity and stress response to the SS2 systemic infection, the precise mechanism underlying bacterial survival and growth within the host bloodstream remains elusive. Here, we reported the SS2 virulent strains with a more than 20 kb endoSS-related insertion region that showed significantly higher proliferative ability in swine serum than low-virulent strains. Further study identified a complete N-glycans degradation system encoded within this insertion region, and found that both GH92 and EndoSS contribute to bacterial virulence, but that only DndoSS was required for optimal growth of SS2 in host serum. The supplement of hydrolyzed high-mannose-containing glycoprotein by GH92 and EndoSS could completely restore the growth deficiency of endoSS deletion mutant in swine serum. EndoSS only hydrolyzed a part of the model glycoprotein RNase B with high-mannose N-linked glycoforms into a low molecular weight form, and the solo activity of GH92 could not show any changes comparing with the blank control in SDS-PAGE gel. However, complete hydrolyzation was observed under the co-incubation of EndoSS and GH92, suggesting GH92 may degrade the high-mannose arms of N-glycans to generate a substrate for EndoSS. In summary, these findings provide compelling evidences that EndoSS-related N-glycans degradation system may enable SS2 to adapt to host serum-specific availability of carbon sources from glycoforms, and be required for optimal colonization and full virulence during systemic infection.

Low and High Molecular Weight FGF-2 Have Differential Effects on Astrocyte Proliferation, but Are Both Protective Against Aβ-Induced Cytotoxicity.

Astrocytes are the most abundant type of glial cells in the brain, and they play a key role in Alzheimer’s disease (AD). Fibroblast Growth Factor-2 (FGF-2) has been implicated as a potential therapeutic agent for treating AD. In the present study, we investigated the protective effects of low molecular weight (LMW; 17 KDa) and high molecular weight (HMW; 23 KDa) forms of FGF-2 on Aβ1–42-induced toxicity, and proliferation in astrocytes. We show that both isoforms of FGF-2 have similar protective effects against Aβ1–42-induced cytotoxicity in primary cultured cortical astrocytes as measured by Lactate Dehydrogenase (LDH) release assay. Additionally, 17 KDa FGF-2 significantly promoted astrocyte proliferation as measured by Trypan Blue, DRAQ5 and 5-ethynyl-2’-deoxyuridine (EdU) staining, but not 23 kDa FGF-2. Furthermore, our results demonstrated that AKT signaling pathway was required for the protective and proliferative effects of FGF-2. Downstream effector studies indicated that 17 kDa FGF-2 promoted astrocyte proliferation by enhanced expression of c-Myc, Cyclin D1, Cyclin E. Furthermore, our data suggested that Cyclin D1 was required for the proliferative effect of LMW FGF2 in astrocytes. Taken together, our findings provide important information for the similarities and differences between 23 kDa and17 kDa isoforms of FGF-2 on astrocyte survival and proliferation.

Middle- and high-molecular weight adiponectin levels in relation to nonalcoholic fatty liver disease.

ObjectiveAdiponectin (APN) circulates as high‐molecular weight (HMW), medium‐molecular weight (MMW), and low‐molecular weight (LMW) forms. Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease. Currently, the role of LMW, MMW, and HMW APN remains largely unclear in NAFLD.MethodsWe examined the variation of these forms and analyzed the related clinical characteristics in NAFLD. A total of 63 male NAFLD patients (mean age: 43.00 ± 6.10 years) and 70 healthy male subjects (mean age: 42.53 ± 7.98 years) were included in the study. Total APN and other clinical characteristics were measured. The changes in HMW, MMW, and LMW APN were determined in NAFLD patients and NAFLD patients on a high‐fat diet, and the association between the groups was further analyzed.ResultsDecreased levels of total APN and three APN isoforms were found in NAFLD. Significantly decreased levels of HMW (P < .01) and MMW (P < .001) were observed in NAFLD of high‐fat diet patients. In NAFLD patients, height (R = −.270, P = .032) and N‐epsilon‐(carboxymethyl) lysine (R = −.259, P = .040) significantly correlated with total APN. HMW APN was significantly associated with fasting plasma glucose (R = .350, P = .016), alanine aminotransferase (R = −.321, P = .029), and aspartate aminotransferase (R = −.295, P = .045). Additionally, MMW APN was significantly associated with total cholesterol (R = .357, P = .014) and high‐density lipoprotein (R = .556, P < .0001). Low‐density lipoprotein (R = −.283, P = .054) was also clearly associated with LMW APN in NAFLD patients.ConclusionThese results suggest that HMW and MMW APN may be involved in the pathogenesis and progression of NAFLD.

Impact of β-catenin phosphorylation patterns on tumour control/progression in a prospective cervical cancer study (RAIDs)

Abstract Background Between 2013 and 2017, the RAIDs consortium conducted a European biobanking study, [BioRAIDs (NCT02428842)] aiming at prospectively annotating cervical cancer (CC) patients and identifying molecular patterns associated with outcome. Dominant oncogenic alterations were reported in PIK3CA (40%), while dominant suppressor gene alterations were seen in KMT2D (15%) and KMT2C (16%). A “metagene” combining these alterations was associated with outcome ( https://doi.org/10.1016/j.ebiom.2019.03.069 ). Methods WES and RPPA data together with PFS at 24 months are available in 89 patients. A boosting approach based on a solid theoretical framework, able to cope with high-dimensional data and censored survival end-points, allowed the identification of innovative potential prognostic markers. Results At a median follow up (FU) of 24 months, progression-free survival (PFS) rates of this FIGO stage IB1-IV population, treated predominantly (87%) by chemoradiation, were 65.4% [CI95%: 60.2-71.1]. In the present analysis, beyond viral clade and FIGO stage, a number of RPPA phospho-protein parameters came up as relevant predictors, associated with better or poorer outcome. Of particular interest is the detection of two different sites for β-catenin phosphorylation (at serine residues 552 and 675), which were associated with prediction of extremes of positive or negative outcome. Conclusions Proteasome-dependant posttranslational modifications to a low molecular weight form of β-catenin phophorylated at COOH-terminal residue S552 has been shown to enhance nuclear translocation and β-catenin/TCF reporter activation possibly through association with histone acetylases (doi: 10.1038/s41598-017-18421-8). Phospho-β-catenin S552 and S675 may predict CC tumor control/progression in patients who failed DNA repair pathway inhibition. Ongoing studies attempt to better define the role of different β-catenin phosphorylations and molecular forms in the BioRAIDS population. Clinical trial identification NCT02428842. Legal entity responsible for the study Institut Curie. Funding The European Union’s Seventh Program for Research, Technological Development and Demonstration under Grant agreement No 304810 and the Fondation ARC pour la Recherche Contre le Cancer. Disclosure All authors have declared no conflicts of interest.