Polymorphisms in the Runx2 and osteocalcin genes affect BMD in postmenopausal women: a systematic review and meta-analysis

PURPOSE

Runx2 and osteocalcin have pivotal roles in bone homeostasis. Polymorphism of these two genes could alter the function of osteoblasts and consequently bone mineral density (BMD). Attempts to understand the relationship between these polymorphisms and BMD in postmenopausal women across a variety of populations have yielded inconsistent results. This meta-analysis seeks to define the relationship between these polymorphisms with BMD in postmenopausal women.

METHODS

Eligible studies were identified from three electronic databases. Data were extracted from the eligible studies (4 studies on Runx2 and 6 studies on osteocalcin), and associations of Runx2 T > C and osteocalcin HindIII polymorphisms with BMD in postmenopausal women were assessed using standard difference in means (SDM) and 95% confidence intervals (CI) as statistical measures.

RESULTS

A significant difference in the lumbar spine (LS) BMD in postmenopausal women was observed between the TT and CC homozygotes for the Runx2 T > C (SDM = -0.445, p-value = 0.034). The mutant genotypes (CC) showed significantly lower LS BMD in comparison to wild type genotypes under recessive model of genetic analysis (TC + TT vs. CC: SDM = -0.451, p-value = 0.032). For osteocalcin, HindIII polymorphism, the mutant genotypes (HH) was associated with significantly higher BMD for both LS and femoral neck (FN) than the wild type (hh) homozygotes (SDM = 0.152, p-value = 0.008 and SDM = 0.139, p-value = 0.016 for LS and FN, respectively). There was no association between total hip (TH) BMD and the osteocalcin HindIII polymorphism.

CONCLUSIONS

Runx2 T > C and osteocalcin HindIII polymorphisms influence the level of BMD in postmenopausal women and may be used as predictive markers of osteoporosis.

All optical modulation in vertically coupled indium tin oxide ring resonator employing epsilon near zero state

We present an innovative approach to achieve all-optical modulation within an ITO-based vertically coupled ring resonator. This method leverages the material's enhanced nonlinear response in the near-infrared wavelengths, particularly within the epsilon-near-zero (ENZ) state. To enhance the interaction between light and the material while minimizing scattering losses, our approach employs an ITO-based vertically connected ring resonator. The vertical arrangement eliminates the need for etching fine gaps to separate the ring and bus waveguide. The novel waveguide design addresses the necessity of high sensitivity, non-linear effects and compact size opening the possibilities for all-optical signal processing. This unique resonator structure effectively facilitates the coupling of a high-intensity pump wavelength into the ITO-based micro-ring resonator. Consequently, this optical pumping induces electron heating within the ITO material, leading to a significant increase in its nonlinear optical properties. This, in turn, results in a noteworthy alteration of ITO's refractive index, specifically in the unity order, thereby modifying the complex effective index of the optical beam propagating at 1550 nm. Our experimental findings demonstrate an impressive extinction ratio of 18 dB for a 30 µm long device, which highlights the efficiency of our approach in achieving all-optical modulation through the optical pumping of an ITO-based vertically coupled ring resonator. The proposed all-optical modulator has outperformed as compared to conventional waveguide-based modulators in terms of extinction ratio and footprint. This novel technique holds immense potential for advancing high-speed data communication systems in the future. As the demand for advanced processing capabilities, such as artificial intelligence, continues to grow, all-optical modulation emerges as a groundbreaking technology poised to revolutionize the next generation of computing and communication systems.

Efficient Nitric Oxide Scavenging by Urea-Functionalized Push-Pull Chromophore Modulates NO-Mediated Diseases

The excess nitric oxide (NO) produced in the body in response to bacterial/proinflammatory stimuli is responsible for several pathological conditions. The current approaches that target the production of excess NO, either through the inhibition of nitric oxide synthase enzyme or its downstream mediators have been clinically unsuccessful. With an aim to regulate the excess NO, urea-functionalized push-pull chromophores containing 1,1,4,4-tetracyanobuta-1,3-dienes (TCBD) or expanded TCBD (eTCBD) were developed as NO scavengers. The NMR mechanistic studies revealed that upon NO binding, these molecules are converted to uncommon stable NONOates. The unique emissive property of Urea-eTCBD enables its application in vitro, as a NO-sensor. Furthermore, the cytocompatible Urea-eTCBD, rapidly inactivated the NO released from LPS-activated cells. The therapeutic efficacy of the molecule in modulating NO-mediated pathological condition was confirmed using a carrageenan-induced inflammatory paw model and a corneal injury model. While the results confirm the advantages of scavenging the excess NO to address a multitude of NO-mediated diseases, the promising sensing and bioactivity of Urea-eTCBD can motivate further exploration of such molecules in allied areas of research.

Hormonal and non-hormonal oral contraceptives given long-term to pubertal rats differently affect bone mass, quality and metabolism

Introduction

We investigated the effects of hormonal and non-hormonal oral contraceptives (OCs) on bone mass, mineralization, composition, mechanical properties, and metabolites in pubertal female SD rats.

Methods

OCs were given for 3-, and 7 months at human equivalent doses. The combined hormonal contraceptive (CHC) was ethinyl estradiol and progestin, whereas the non-hormonal contraceptive (NHC) was ormeloxifene. MicroCT was used to assess bone microarchitecture and BMD. Bone formation and mineralization were assessed by static and dynamic histomorphometry. The 3-point bending test, nanoindentation, FTIR, and cyclic reference point indentation (cRPI) measured the changes in bone strength and material composition. Bone and serum metabolomes were studied to identify potential biomarkers of drug efficacy and safety and gain insight into the underlying mechanisms of action of the OCs.

Results

NHC increased bone mass in the femur metaphysis after 3 months, but the gain was lost after 7 months. After 7 months, both OCs decreased bone mass and deteriorated trabecular microarchitecture in the femur metaphysis and lumbar spine. Also, both OCs decreased the mineral: matrix ratio and increased the unmineralized matrix after 7 months. After 3 months, the OCs increased carbonate: phosphate and carbonate: amide I ratios, indicating a disordered hydroxyapatite crystal structure susceptible to resorption, but these changes mostly reversed after 7 months, indicating that the early changes contributed to demineralization at the later time. In the femur 3-point bending test, CHC reduced energy storage, resilience, and ultimate stress, indicating increased susceptibility to micro-damage and fracture, while NHC only decreased energy storage. In the cyclic loading test, both OCs decreased creep indentation distance, but CHC increased the average unloading slope, implying decreased microdamage risk and improved deformation resistance by the OCs. Thus, reduced bone mineralization by the OCs appears to affect bone mechanical properties under static loading, but not its cyclic loading ability. When compared to an age-matched control, after 7 months, CHC affected 24 metabolic pathways in bone and 9 in serum, whereas NHC altered 17 in bone and none in serum. 6 metabolites were common between the serum and bone of CHC rats, suggesting their potential as biomarkers of bone health in women taking CHC.

Conclusion

Both OCs have adverse effects on various skeletal parameters, with CHC having a greater negative impact on bone strength.

Post-Implantation Stiffening by a Bioinspired, Double-Network, Self-Healing Hydrogel Facilitates Minimally Invasive Cell Delivery for Cartilage Regeneration

Injectable hydrogels have demonstrated advantages in cartilage repair by enabling the delivery of cells through a minimally invasive approach. However, several injectable hydrogels suffer from rapid degradation and low mechanical strength. Moreover, higher mechanical stiffness in hydrogels can have a detrimental effect on post-implantation cell viability. To address these challenges, we developed an in situ forming bioinspired double network hydrogel (BDNH) that exhibits temperature-dependent stiffening after implantation. The BDNH mimics the microarchitecture of aggrecan, with hyaluronic acid-conjugated poly(N-isopropylacrylamide) providing rigidity and Schiff base crosslinked polymers serving as the ductile counterpart. BDNHs exhibited self-healing property and enhanced stiffness at physiological temperature. Excellent cell viability, long time cell proliferation, and cartilage specific matrix production were observed in the chondrocytes cultured in the BDNH hydrogel. Evidence of cartilage regeneration in a rabbit cartilage defect model using chondrocyte-laden BDNH has suggested it to be a potential candidate for cartilage tissue engineering.

Taurine deficiency as a driver of aging

Aging is associated with changes in circulating levels of various molecules, some of which remain undefined. We find that concentrations of circulating taurine decline with aging in mice, monkeys, and humans. A reversal of this decline through taurine supplementation increased the health span (the period of healthy living) and life span in mice and health span in monkeys. Mechanistically, taurine reduced cellular senescence, protected against telomerase deficiency, suppressed mitochondrial dysfunction, decreased DNA damage, and attenuated inflammaging. In humans, lower taurine concentrations correlated with several age-related diseases and taurine concentrations increased after acute endurance exercise. Thus, taurine deficiency may be a driver of aging because its reversal increases health span in worms, rodents, and primates and life span in worms and rodents. Clinical trials in humans seem warranted to test whether taurine deficiency might drive aging in humans.

Injectable Bone Cement Reinforced with Gold Nanodots Decorated rGO-Hydroxyapatite Nanocomposites, Augment Bone Regeneration

Interest in the development of new generation injectable bone cements having appropriate mechanical properties, biodegradability, and bioactivity has been rekindled with the advent of nanoscience. Injectable bone cements made with calcium sulfate (CS) are of significant interest, owing to its compatibility and optimal self-setting property. Its rapid resorption rate, lack of bioactivity, and poor mechanical strength serve as a deterrent for its wide application. Herein, a significantly improved CS-based injectable bone cement (modified calcium sulfate termed as CS_mod ), reinforced with various concentrations (0-15%) of a conductive nanocomposite containing gold nanodots and nanohydroxyapatite decorated reduced graphene oxide (rGO) sheets (AuHp@rGO), and functionalized with vancomycin, is presented. The piezo-responsive cement exhibits favorable injectability and setting times, along with improved mechanical properties. The antimicrobial, osteoinductive, and osteoconductive properties of the CS_mod cement are confirmed using appropriate in vitro studies. There is an upregulation of the paracrine signaling mediated crosstalk between mesenchymal stem cells and human umbilical vein endothelial cells seeded on these cements. The ability of CS_mod to induce endothelial cell recruitment and augment bone regeneration is evidenced in relevant rat models. The results imply that the multipronged activity exhibited by the novel-CS_mod cement would be beneficial for bone repair.

Efficacy of antiresorptive agents bisphosphonates and denosumab in mitigating hypercalcemia and bone loss in primary hyperparathyroidism: A systematic review and meta-analysis

PURPOSE

Primary hyperparathyroidism (PHPT) is characterized by increased bone remodeling and hypercalcemia. Parathyroidectomy (PTX), the current standard of care, is recommended in all symptomatic and some groups of asymptomatic patients. Anti-resorptive therapies (bisphosphonates and denosumab) have been used in patients where PTX is refused or contraindicated. In this meta-analysis, we investigated the effectiveness of anti-resorptives in preventing/treating PHPT-induced bone loss and mitigating hypercalcemia.

METHOD

PubMed, Scopus, and Cochrane Library databases were searched for articles with keywords containing PHPT, bisphosphonates, and denosumab in various combinations. We extracted and tabulated areal BMD (aBMD), serum mineral, and bone turnover parameters from the qualified studies and used comprehensive meta-analysis software for analysis.

RESULTS

Of the 1,914 articles screened, 13 were eligible for meta-analysis. In the pooled analysis, 12 months of anti-resoptives (bisphosphonates and denosumab) therapy significantly increased aBMD at the lumbar spine (Standard difference in means (SDM)=0.447, 95% CI=0.230 to 0.664, p=0.0001), femoral neck (SDM=0.270, 95% CI=0.049 to 0.491, p=0.017) and increased serum PTH (SDM=0.489, 95% CI=0.139 to 0.839, p=0.006), and decreased serum calcium (SDM=-0.545, 95% CI=-0.937 to -0.154, p=0.006) compared with baseline. 12 months of bisphosphonate use significantly increased aBMD only at the lumbar spine (SDM=0.330, 95% CI=0.088 to 0.571, p=0.007) with a significant increased in serum PTH levels (SDM=0.546, 95% CI= 0.162 to 0.930, p=0.005), and a decreased in serum calcium (SDM=-0.608, 95% CI=-1.048 to -0.169, p=0.007) and bone-turnover markers (BTMs) compared with baseline. Denosumab use for 12 months significantly increased aBMD at both the lumbar spine (SDM=0.828, 95% CI=0.378 to 1.278, p=0.0001) and femur neck (SDM=0.575, 95% CI=0.135 to 1.015, p=0.010) compared with baseline. Mean lumbar spine aBMD (SDM=0.350, 95% CI=0.041 to 0.659, p=0.027) and serum PTH (SDM=0.602, 95% CI= 0.145 to 1.059, p=0.010) were significantly increased after 12 months of alendronate use compared with placebo. When compared with baseline, alendronate significantly decreased BTMs after 12 months and increased aBMD without altering the PTH and calcium levels after 24 months.

CONCLUSION

Anti-resorptives are effective in mitigating bone loss and hypercalcemia in PHPT while maintaining or increasing aBMD. PTX reversed all changes in PHPT and normalized PTH levels.

A standardized extract of Coleus forskohlii root protects rats from ovariectomy-induced loss of bone mass and strength, and impaired bone material by osteogenic and anti-resorptive mechanisms

INTRODUCTION

In obese humans, Coleus forskohlii root extract (CF) protects against weight gain owing to the presence of forskolin, an adenylate cyclase (AC) activator. As AC increases intracellular cyclic adenosine monophosphate (cAMP) levels in osteoblasts that has an osteogenic effect, we thus tested the skeletal effects of a standardized CF (CFE) in rats.

METHODS

Concentrations of forskolin and isoforskolin were measured in CFE by HPLC. CFE and forskolin (the most abundant compound present in CFE) were studied for their osteogenic efficacy in vitro by alkaline phosphatase (ALP), cAMP and cyclic guanosine monophosphate (cGMP) assays. Femur osteotomy model was used to determine the osteogenic dose of CFE. In growing rats, CFE was tested for its osteogenic effect in intact bone. In adult ovariectomized (OVX) rats, we assessed the effect of CFE on bone mass, strength and material. The effect of forskolin was assessed in vivo by measuring the expression of osteogenic genes in the calvarium of rat pups.

RESULTS

Forskolin content in CFE was 20.969%. CFE increased osteoblast differentiation and intracellular cAMP and cGMP levels in rat calvarial osteoblasts. At 25 mg/kg (half of human equivalent dose), CFE significantly enhanced calcein deposition at the osteotomy site. In growing rats, CFE promoted modeling-directed bone formation. In OVX rats, CFE maintained bone mass and microarchitecture to the level of sham-operated rats. Moreover, surface-referent bone formation in CFE treated rats was significantly increased over the OVX group and was comparable with the sham group. CFE also increased the pro-collagen type-I N-terminal propeptide: cross-linked C-telopeptide of type-I collagen (PINP : CTX-1) ratio over the OVX rats, and maintained it to the sham level. CFE treatment decreased the OVX-induced increases in the carbonate-to-phosphate, and carbonate-to-amide-I ratios. CFE also prevented the OVX-mediated decrease in mineral crystallinity. Nanoindentation parameters, including modulus and hardness, were decreased by OVX but CFE maintained these to the sham levels. Forskolin stimulated ALP, cAMP and cGMP in vitro and upregulated osteogenic genes in vivo.

CONCLUSION

CFE, likely due to the presence of forskolin displayed a bone-conserving effect via osteogenic and anti-resorptive mechanisms resulting in the maintenance of bone mass, microarchitecture, material, and strength.

Diosmin, a citrus fruit-derived phlebotonic bioflavonoid protects rats from chronic kidney disease-induced loss of bone mass and strength without deteriorating renal function

Kidney Disease: Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline recommended treatment decisions for patients with chronic kidney disease (CKD) with osteoporosis and/or high risk of fracture. Bisphosphonates, the first-line...

A novel extraction method enhanced the osteogenic and anti-osteoporosis effect of tea extract without any hepatotoxicity in ovariectomized rats

Tea (Camellia sinensis) has several reported health benefits, including that on bone health attributed to catechins of which the most abundant is epigallocatechin-3-gallate (EGCG). However, several preclinical and clinical studies raise safety concerns about EGCG in tea extract causing acute liver failure. Tea also contains kaempferol, albeit scanty, and it has hepatoprotective and osteogenic effects. Here, we utilized a novel extraction procedure of acid hydrolysis to enhance the osteogenic effect of tea extract while reducing its hepatotoxicity. The resultant extract (USKECSE) has a ~40-fold increase in kaempferol and a 2.5-fold reduction in EGCG content compared with the hydroethanolic extract (USCSE). In a female Sprague Dawley (SD) rat femur osteotomy model, USKECSE (100 mg/kg) but not USCSE promoted bone regeneration. In a rat postmenopausal osteoporosis model induced by bilateral ovariectomy (OVX), USKECSE through an osteogenic mechanism maintained bone mass, strength, and microarchitecture to the levels of ovary-intact rats with no hepatotoxic effect. After a single oral dose (100 mg/kg) of USKECSE to adult rats, kaempferol was detectable for 48 hours, suggesting its significant absorption and distribution in plasma. Peak kaempferol concentration in plasma (C_max) was 483 ng/ml (2 μM), and at this concentration, kaempferol induces osteoblast differentiation. USKECSE had no genotoxicity, and its safety index assessed by preclinical toxicity studies, including safety pharmacology, was >20-fold. Taken together, we report a novel extraction process that enhanced the osteogenicity and concomitantly reduced hepatotoxicity of tea extract with significant kaempferol bioavailability and a favorable systemic safety profile. Based on these data, we propose assessing the USKECSE effect for postmenopausal osteoporosis treatment.

A naphthalimide-based peptide conjugate for concurrent imaging and apoptosis induction in cancer cells by utilizing endogenous hydrogen sulfide

The excessive production of endogenous hydrogen sulfide (H2S) in cancer cells leads to enhanced tumor growth and metastasis. On the other hand, decreased endogenous H2S suppresses tumor growth. The reported approaches for inhibiting tumor growth are selective silencing of the tumor-promoting genes and pharmacological inhibition of these proteins. To enhance the antitumor efficacy of frontline chemotherapeutic agents, herein, we synthesized a highly sensitive endogenous H2S responsive fluorescent probe, i.e., a hydrogen sulfide-sensing naphthalimide-based peptide conjugate (HSNPc), which showed selective inhibition of proliferation of cancer cells due to apoptosis induction. Furthermore, HSNPc suppressed the glycolytic reserve, a critical energy source for the proliferation of cancer cells. HSNPc also decreased the Young's modulus of HeLa cells compared to the control cells, which demonstrated a direct relation between cell apoptosis and cell stiffness. Taken together, we demonstrated the dual function of detection and killing of cancer cells by HSNPc that can be likened to a theranostic role.

Comparison of Fluorometric and UV Spectrophotometric Findings for DNA Isolated From Formalin-Fixed Paraffin-Embedded Blocks, Fine Needle Aspiration Cytology Smears, and Blood

Introduction: Fine needle aspiration cytology (FNAC) smear may serve as a convenient sample for DNA extraction for molecular pathology in addition to more commonly used formalin-fixed paraffin-embedded (FFPE) sections. DNA quantification done by fluorometer is more accurate than UV vis spectrophotometer regardless of the source. This study was conducted to compare DNA yield and quality from cytology smears, FFPE sections and peripheral blood using both fluorometer and spectrophotometer. Further, introspection was made to check for the adequacy of DNA extracted from cytology smears with respect to DNA extracted from core biopsies.

Method: DNA was extracted from 10 fresh peripheral blood samples, core biopsies and FNAC smears. The DNA was quantified using a fluorimeter and UV vis spectrophotometer in all cases.

Results: Statistically significant difference was seen between the data obtained from UV vis spectrophotometry and flourometry. The quantity of DNA extracted from FNAC smears was higher than that of core biopsy as per fluorometry data (mean DNA of core biopsy = 1.9ng/µl, of FNAC = 3.3ng/µl).

Conclusion: DNA estimation by fluorometry is more accurate and precise than spectrophotometry in FFPE, FNAC and whole blood samples. DNA yield from FNAC slides is comparable to that from core biopsies.

Adiponectin receptors by increasing mitochondrial biogenesis and respiration promote osteoblast differentiation: Discovery of isovitexin as a new class of small molecule adiponectin receptor modulator with potential osteoanabolic function

Previously, we established adiponectin receptors (AdipoRs) as osteoanabolic target. To discover small molecule agonists of AdipoRs, we studied apigenin and apigenin-6C-glucopyranose (isovitexin) that induced osteoblast differentiation. In-silico, in vitro and omics-based studies were performed. Molecular docking using the crystal structures of AdipoRs showed different interaction profiles of isovitexin and apigenin. In osteoblasts, isovitexin but not apigenin rapidly phosphorylated AMP-activated protein kinase (pAMPK) which is downstream of AdipoRs and a master regulator of cellular energy metabolism, and upregulated expression of AdipoRs. Blocking AMPK abolished the osteogenic effect of isovitexin and its effect on AdipoR expression. Isovitexin upregulated the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), the mitochondrial biogenesis factor in osteoblasts, and the effect was blocked by AMPK inhibition. Upregulation of PGC-1α by isovitexin was accompanied by increased mitochondrial membrane proteins and mitochondrial DNA (mtDNA). Isovitexin via AdipoRs and PGC-1α induced oxidative phosphorylation (OxPhos) and ATP synthesis that resulted in osteoblast differentiation. Isovitexin had no agonistic/antagonistic activity and stimulatory/inhibitory effect in screening platforms for G protein-coupled receptors and kinases, respectively. In vivo, isovitexin upregulated AdipoRs and osteogenic genes, and increased mtDNA in rat calvarium. We conclude that isovitexin selectively via AdipoRs induced osteoblast differentiation that was fuelled by mitochondrial respiration.

An injectable hydrogel having proteoglycan-like hierarchical structure supports chondrocytes delivery and chondrogenesis

The ECM of cartilage is composed of proteoglycans (PG) that contain glycosaminoglycan (GAG), aggrecan, hyaluronic acid (HA) and other molecular components which play an important role in regulating chondrocyte functions via cell-matrix interactions, integrin-mediated signalling etc. Implantation of chondrocytes encapsulated in scaffolds that mimic the micro-architecture of proteoglycan, is expected to enhance cartilage repair. With an aim to create a hydrogel having macromolecular structure that resembles the cartilage-specific ECM, we constructed a hierarchal structure that mimic the PG. The bottle brush structure of the aggrecan was obtained using chondroitin sulphate and carboxymethyl cellulose which served as GAG and core protein mimic respectively. A proteoglycan-like structure was obtained by cross-linking it with modified chitosan that served as a HA substitute. The physico-chemical characteristics of the above cross-linked injectable hydrogel supported long term human articular chondrocyte subsistence and excellent post-injection viability. The chondrocytes encapsulated in the PMH expressed significant levels of articular cartilage specific markers like collagen II, aggrecan, GAGs etc., indicating the ability of the hydrogel to support chondrocyte differentiation. The biocompatibility and biodegradability of the hydrogels was confirmed using suitable in vivo studies. The results revealed that the PG-mimetic hydrogel could serve as a promising scaffold for chondrocyte implantation.

Tunable, conductive, self-healing, adhesive and injectable hydrogels for bioelectronics and tissue regeneration applications

Conductive hydrogels are attracting considerable interest in view of their potential in a wide range of applications that include healthcare and electronics. Such hydrogels are generally incorporated with conductive materials/polymers. Herein, we present a series of conductive hydrogels (Ch-CMC-PDA), prepared with no additional conductive material. The hydrogels were synthesized using a combination of chitosan, cellulose (CMC) and dopamine (DA). The conductivity (0.01-3.4 × 10^-3 S cm^-1) in these gels is attributed to ionic conductivity. Very few conductive hydrogels are endowed with additional properties like injectability, adhesiveness and self-healing, which would help to widen their scope for applications. While the dynamic Schiff base coupling in our hydrogels facilitated self-healing and injectable properties, polydopamine imparted tissue adhesiveness. The porosity, rheological, mechanical and conductive properties of the hydrogels are regulated by the CMC-dialdehyde-polydopamine (CMC-D-PDA) content. The hydrogel was evaluated in various bioelectronics applications like ECG monitoring and triboelectric nanogenerators (TENG). The ability of the hydrogel to support cell growth and serve as a template for tissue regeneration was confirmed using in vitro and in vivo studies. In summary, the integration of such remarkable features in the ionic-conductive hydrogel would enable its usage in bioelectronics and biomedical applications.

Soft-Dielectron Excess in Proton-Proton Collisions at sqrt[s]=13 TeV

A measurement of dielectron production in proton-proton (pp) collisions at sqrt[s]=13  TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass m_{ee} and pair transverse momentum p_{T,ee} that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of m_{ee}, p_{T,ee}, and event multiplicity dN_{ch}/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π^{0} ratio in pp and proton-nucleus collisions, assuming that this ratio shows no strong dependence on collision energy at low transverse momentum. Comparison of the measured dielectron yield to the hadronic cocktail at 0.15<m_{ee}<0.6  GeV/c^{2} and for p_{T,ee}<0.4  GeV/c indicates an enhancement of soft dielectrons, reminiscent of the "anomalous" soft-photon and soft-dilepton excess in hadron-hadron collisions reported by several experiments under different experimental conditions. The enhancement factor over the hadronic cocktail amounts to 1.61±0.13(stat)±0.17(syst,data)±0.34(syst,cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in m_{ee} and p_{T,ee} are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.

Optical modulator based on a silicon-ITO grating embedded rib structure with a tunable group delay

An optical modulator based on an engineered silicon-indium tin oxide (Si-ITO) structure is proposed with a tunable group delay. A large group delay is reported by slowing down the light in a Si-ITO grating embedded rib structure. Optical modulation and a tunable group delay are realized by utilizing the electrically tunable permittivity of ITO in the engineered waveguide. The extinction ratio over 8 dB for a 10 µm long device and the modulation efficiency around 12 V-µm are reported for a wide wavelength from 1530 to 1570 nm. The resulting modulation efficiency and the extinction ratio show a significant improvement as compared to conventional modulators based on rib waveguides. We also report around 82 psec electrical tuning in the group delay for a wide wavelength range. This concept is promising in view of realizing tunable delay lines, along with slow light modulators with a reduced device footprint and low energy dissipation.

COVID-19 and Gut Microbiota: A Potential Connection

Currently, world is facing a global outbreak causing a pandemic threat known as COVID-19. This infectious disease is triggered by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Gut microbiota harbours multi species community with a strong impact on host immune homeostasis. However, our knowledge about this gut microbiota and its symbiotic relationship with immune activation in association with SARS-CoV-2 is limited. Unbalanced bacterial flora with too many opportunistic infections can shift immune system towards a cascade of inflammatory responses leading to multi organ damage. This review will highlight immune-regulation via various mechanisms in SARS-CoV-2 infection. Diet has an unbelievable influence on gut microbiome that allows a new state of homeostasis to be reached through timing, frequency and duration of intake. This review article focuses on gut, lung microbiota and immunomodulation with specific attention on immune activation by gut microbiota.

Human Relevance of Preclinical Studies on the Skeletal Impact of Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

Inflammatory bowel disease (IBD) is a relapsing chronic idiopathic inflammatory condition. The increased risks of fractures in the spine and decreased BMD at all weight-bearing skeletal sites have been reported in IBD patients. The understanding of the mechanisms of IBD-induced bone loss is far from complete. Appropriate animal models are a prerequisite for studying IBD-induced bone loss, which prompted us to undertake quantitative meta-analyses by pooling data from the available IBD models that assessed various bone parameters. Sufficient data for meta-analysis are obtained from chemically- but not genetically induced models. Among the chemically induced models, only the effects of dextran sulfate sodium (DSS) and 2,4,6-trinitrobenzene sulfonic acid (TNBS) on bone parameters have been reported. Meta-analysis showed that both DSS (Hedge's g = 2.124, p = 0.001) and TNBS (Hedge's g = 6.292, p = 0.000) increased inflammatory disease severity. In pooled analysis, bone volumes in femur (Hedge's g = - 3.42, p = 0.000) and tibia (Hedge's g = - 2.49, p = 0.000) showed significant losses upon DSS administration. Similarly, bone formation rate was significantly reduced upon IBD induction (Hedge's g = - 3.495, p = 0.006). Besides, cortical thickness was reduced and trabecular microstructure deteriorated by IBD induction. Insufficient data precluded us from determining the effect of IBD on bone strength and calciotropic hormones, as well as the impact of proinflammatory cytokines on bone turnover. This meta-analysis showed that IBD induction in rodents causes significant bone loss. Impaired osteoblast function appears to be the cause of this impact.

Optical switch with ultra high extinction ratio using electrically controlled metal diffusion

An optical switch with ultra high extinction ratio is proposed. Optical switching is realized using the resistive switching effect through the lateral coupling between the input nanophotonic waveguide and output waveguide at a wavelength of 1550 nm. The coupled waveguide system is engineered to increase the number of mode beats in a unit length of the device. An increase in the number of mode beats and controlled diffusion of metal ions through a thin dielectric layer with an applied electric field is responsible for a high optical extinction ratio of 27 dB for a 20 µm long device. Compared to electrical control by plasma dispersion in silicon, the resistive switching effect enables a reduction in the coupling length and an increase in the waveguide absorption, leading to an almost 100 times higher extinction ratio. The proposed compact on-chip silicon-based nanophotonic resistive device is a potential candidate for a large-scale integrated photonic circuit for applications in optical switching, modulation, memory, and computation.

Engineered nanophotonic waveguide with ultra-low dispersion

A silicon-based engineered hybrid plasmonic waveguide with ultra-low dispersion is proposed. The ridge-shaped structure of the nanophotonic waveguide enables nano-scale confinement with electrically tunable characteristics using the plasma dispersion effect in silicon. The waveguide exhibits ultra-low dispersion of $1.28\;{{\rm ps}^2}/{\rm m}$ at telecommunication wavelength (1550 nm) in C band together with dual flatband dispersion over a wavelength range of 370 nm. The hybrid plasmonic mode is made to be confined in 15 nm thick ${{\rm SiO}_2}$ with a propagation loss of 15.3 dB/mm utilizing the engineered ridge structure comprising Si, ${{\rm SiO}_2}$, and gold. In addition, the proposed waveguide shows six zero-dispersion wavelengths. The imaginary and real parts of the effective refractive index of the guided hybrid plasmonic mode are reported to be tunable with the applied voltage. The reported numerical results can pave the way for achieving intensity modulators and other electrically tunable devices at telecommunication wavelengths. The ultra-low dispersion and electrical tuning make this nanophotonic waveguide an absolute contender for applications including efficient nonlinear signal processing such as wide wavelength conversion based on four-wave mixing, supercontinuum generation, and other nanoscale integrated photonic devices.

Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v_{2}. The v_{2} coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum (p_{T}) range 1.3-6  GeV/c in the centrality class 30%-50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length cτ≈500  μm compared to that of charm hadrons and most of the other background sources. The v_{2} of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75  σ. The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high p_{T}, but is in agreement with the results at low p_{T}. Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties.

Prevalence of Vitamin D Deficiency Among Infants in Northern India: A Hospital Based Prospective Study

Background: Vitamin D deficiency is one of the major nutritional deficiencies and an important contributor to nutritional and growth failure in infants, especially in those with low socioeconomic status.

Aim: The primary objective of this study was to determine the proportion of vitamin D deficiency in infants, and the secondary objective was to assess the correlation between infant and maternal vitamin D levels.

Methods: This prospective, observational study was carried out at a tertiary care center, All India Institute of Medical Sciences in Rishikesh, Uttarakhand, India, in the Department of Pediatrics from January 2017 to December 2018. Children aged less than one year and their mothers were enrolled in the study. All the infants attending the Department of Pediatrics for well-child visits and sick-child visits were enrolled after obtaining written, informed consent. Infants with major congenital malformations and liver and kidney dysfunction were excluded. Serum vitamin D level of <20 ng/mL was defined as vitamin D deficiency.

Results: A total of 200 infants and 200 mothers were enrolled in the study. Among the study infants, 80% were neonates, and 20% were infants beyond the neonatal period. The prevalence of vitamin D deficiency was 74% in infants and 85.5% in mothers. Nearly half of the infants and mothers had severe vitamin D deficiency. Logistic regression analysis showed a positive correlation between maternal and infant vitamin D levels (r=0.074, p<0.001) and also with neonatal age group and low socioeconomic status. Hyperphosphatemia and hypocalcemia were predominant biochemical manifestations.

Conclusion: The prevalence of vitamin D deficiency among the study infants was 74%. Neonatal age group, lower socioeconomic status, and maternal vitamin D deficiency were major determinants of vitamin D deficiency in infants.

Measurement of the Low-Energy Antideuteron Inelastic Cross Section

In this Letter, we report the first measurement of the inelastic cross section for antideuteron-nucleus interactions at low particle momenta, covering a range of 0.3≤p<4  GeV/c. The measurement is carried out using p-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of sqrt[s_{NN}]=5.02  TeV, recorded with the ALICE detector at the CERN LHC and utilizing the detector material as an absorber for antideuterons and antiprotons. The extracted raw primary antiparticle-to-particle ratios are compared to the results from detailed ALICE simulations based on the geant4 toolkit for the propagation of (anti)particles through the detector material. The analysis of the raw primary (anti)proton spectra serves as a benchmark for this study, since their hadronic interaction cross sections are well constrained experimentally. The first measurement of the inelastic cross section for antideuteron-nucleus interactions averaged over the ALICE detector material with atomic mass numbers ⟨A⟩=17.4 and 31.8 is obtained. The measured inelastic cross section points to a possible excess with respect to the Glauber model parametrization used in geant4 in the lowest momentum interval of 0.3≤p<0.47  GeV/c up to a factor 2.1. This result is relevant for the understanding of antimatter propagation and the contributions to antinuclei production from cosmic ray interactions within the interstellar medium. In addition, the momentum range covered by this measurement is of particular importance to evaluate signal predictions for indirect dark-matter searches.

Probing the Effects of Strong Electromagnetic Fields with Charge-Dependent Directed Flow in Pb-Pb Collisions at the LHC

The first measurement at the LHC of charge-dependent directed flow (v_{1}) relative to the spectator plane is presented for Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV. Results are reported for charged hadrons and D^{0} mesons for the transverse momentum intervals p_{T}>0.2  GeV/c and 3<p_{T}<6  GeV/c in the 5%-40% and 10%-40% centrality classes, respectively. The difference between the positively and negatively charged hadron v_{1} has a positive slope as a function of pseudorapidity η, dΔv_{1}/dη=[1.68±0.49(stat)±0.41(syst)]×10^{-4}. The same measurement for D^{0} and D[over ¯]^{0} mesons yields a positive value dΔv_{1}/dη=[4.9±1.7(stat)±0.6(syst)]×10^{-1}, which is about 3 orders of magnitude larger than the one of the charged hadrons. These measurements can provide new insights into the effects of the strong electromagnetic field and the initial tilt of matter created in noncentral heavy ion collisions on the dynamics of light (u, d, and s) and heavy (c) quarks. The large difference between the observed Δv_{1} of charged hadrons and D^{0} mesons may reflect different sensitivity of the charm and light quarks to the early time dynamics of a heavy ion collision. These observations challenge some recent theoretical calculations, which predicted a negative and an order of magnitude smaller value of dΔv_{1}/dη for both light flavor and charmed hadrons.

Evidence of Spin-Orbital Angular Momentum Interactions in Relativistic Heavy-Ion Collisions

The first evidence of spin alignment of vector mesons (K^{*0} and ϕ) in heavy-ion collisions at the Large Hadron Collider (LHC) is reported. The spin density matrix element ρ_{00} is measured at midrapidity (|y|<0.5) in Pb-Pb collisions at a center-of-mass energy (sqrt[s_{NN}]) of 2.76 TeV with the ALICE detector. ρ_{00} values are found to be less than 1/3 (1/3 implies no spin alignment) at low transverse momentum (p_{T}<2  GeV/c) for K^{*0} and ϕ at a level of 3σ and 2σ, respectively. No significant spin alignment is observed for the K_{S}^{0} meson (spin=0) in Pb-Pb collisions and for the vector mesons in pp collisions. The measured spin alignment is unexpectedly large but qualitatively consistent with the expectation from models which attribute it to a polarization of quarks in the presence of angular momentum in heavy-ion collisions and a subsequent hadronization by the process of recombination.

mTORC2 Is Involved in the Induction of RSK Phosphorylation by Serum or Nutrient Starvation

Cells adjust to nutrient fluctuations to restore metabolic homeostasis. The mechanistic target of rapamycin (mTOR) complex 2 responds to nutrient levels and growth signals to phosphorylate protein kinases belonging to the AGC (Protein Kinases A,G,C) family such as Akt and PKC. Phosphorylation of these AGC kinases at their conserved hydrophobic motif (HM) site by mTORC2 enhances their activation and mediates the functions of mTORC2 in cell growth and metabolism. Another AGC kinase family member that is known to undergo increased phosphorylation at the homologous HM site (Ser380) is the p90 ribosomal S6 kinase (RSK). Phosphorylation at Ser380 is facilitated by the activation of the mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) in response to growth factor stimulation. Here, we demonstrate that optimal phosphorylation of RSK at this site requires an intact mTORC2. We also found that RSK is robustly phosphorylated at Ser380 upon nutrient withdrawal or inhibition of glycolysis, conditions that increase mTORC2 activation. However, pharmacological inhibition of mTOR did not abolish RSK phosphorylation at Ser380, indicating that mTOR catalytic activity is not required for this phosphorylation. Since RSK and SIN1β colocalize at the membrane during serum restimulation and acute glutamine withdrawal, mTORC2 could act as a scaffold to enhance RSK HM site phosphorylation. Among the known RSK substrates, the CCTβ subunit of the chaperonin containing TCP-1 (CCT) complex had defective phosphorylation in the absence of mTORC2. Our findings indicate that the mTORC2-mediated phosphorylation of the RSK HM site could confer RSK substrate specificity and reveal that RSK responds to nutrient fluctuations.

Scattering Studies with Low-Energy Kaon-Proton Femtoscopy in Proton-Proton Collisions at the LHC

The study of the strength and behavior of the antikaon-nucleon (K[over ¯]N) interaction constitutes one of the key focuses of the strangeness sector in low-energy quantum chromodynamics (QCD). In this Letter a unique high-precision measurement of the strong interaction between kaons and protons, close and above the kinematic threshold, is presented. The femtoscopic measurements of the correlation function at low pair-frame relative momentum of (K^{+}p⊕K^{-}p[over ¯]) and (K^{-}p⊕K^{+}p[over ¯]) pairs measured in pp collisions at sqrt[s]=5, 7, and 13 TeV are reported. A structure observed around a relative momentum of 58  MeV/c in the measured correlation function of (K^{-}p⊕K^{+}p[over ¯]) with a significance of 4.4σ constitutes the first experimental evidence for the opening of the (K[over ¯]^{0}n⊕K^{0}n[over ¯]) isospin breaking channel due to the mass difference between charged and neutral kaons. The measured correlation functions have been compared to Jülich and Kyoto models in addition to the Coulomb potential. The high-precision data at low relative momenta presented in this work prove femtoscopy to be a powerful complementary tool to scattering experiments and provide new constraints above the K[over ¯]N threshold for low-energy QCD chiral models.

Measurement of ϒ(1S) Elliptic Flow at Forward Rapidity in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The first measurement of the ϒ(1S) elliptic flow coefficient (v_{2}) is performed at forward rapidity (2.5<y<4) in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC. The results are obtained with the scalar product method and are reported as a function of transverse momentum (p_{T}) up to 15  GeV/c in the 5%-60% centrality interval. The measured ϒ(1S)v_{2} is consistent with 0 and with the small positive values predicted by transport models within uncertainties. The v_{2} coefficient in 2<p_{T}<15  GeV/c is lower than that of inclusive J/ψ mesons in the same p_{T} interval by 2.6 standard deviations. These results, combined with earlier suppression measurements, are in agreement with a scenario in which the ϒ(1S) production in Pb-Pb collisions at LHC energies is dominated by dissociation limited to the early stage of the collision, whereas in the J/ψ case there is substantial experimental evidence of an additional regeneration component.

Investigations of Anisotropic Flow Using Multiparticle Azimuthal Correlations in pp, p-Pb, Xe-Xe, and Pb-Pb Collisions at the LHC

Measurements of anisotropic flow coefficients (v_{n}) and their cross-correlations using two- and multiparticle cumulant methods are reported in collisions of pp at sqrt[s]=13  TeV, p-Pb at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02  TeV, Xe-Xe at sqrt[s_{NN}]=5.44  TeV, and Pb-Pb at sqrt[s_{NN}]=5.02  TeV recorded with the ALICE detector. The multiplicity dependence of v_{n} is studied in a very wide range from 20 to 3000 particles produced in the midrapidity region |η|<0.8 for the transverse momentum range 0.2<p_{T}<3.0  GeV/c. An ordering of the coefficients v_{2}>v_{3}>v_{4} is found in pp and p-Pb collisions, similar to that seen in large collision systems, while a weak v_{2} multiplicity dependence is observed relative to nucleus-nucleus collisions in the same multiplicity range. Using a novel subevent method, v_{2} measured with four-particle cumulants is found to be compatible with that from six-particle cumulants in pp and p-Pb collisions. The magnitude of the correlation between v_{n}^{2} and v_{m}^{2}, evaluated with the symmetric cumulants SC(m,n) is observed to be positive at all multiplicities for v_{2} and v_{4}, while for v_{2} and v_{3} it is negative and changes sign for multiplicities below 100, which may indicate a different v_{n} fluctuation pattern in this multiplicity range. The observed long-range multiparticle azimuthal correlations in high multiplicity pp and p-Pb collisions can neither be described by pythia 8 nor by impact-parameter-Glasma, music, and ultrarelativistic quantum molecular dynamics model calculations, and hence, provide new insights into the understanding of collective effects in small collision systems.

First Observation of an Attractive Interaction between a Proton and a Cascade Baryon

This Letter presents the first experimental observation of the attractive strong interaction between a proton and a multistrange baryon (hyperon) Ξ^{-}. The result is extracted from two-particle correlations of combined p-Ξ^{-}⊕p[over ¯]-Ξ[over ¯]^{+} pairs measured in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV at the LHC with ALICE. The measured correlation function is compared with the prediction obtained assuming only an attractive Coulomb interaction and a standard deviation in the range [3.6, 5.3] is found. Since the measured p-Ξ^{-}⊕p[over ¯]-Ξ[over ¯]^{+} correlation is significantly enhanced with respect to the Coulomb prediction, the presence of an additional, strong, attractive interaction is evident. The data are compatible with recent lattice calculations by the HAL-QCD Collaboration, with a standard deviation in the range [1.8, 3.7]. The lattice potential predicts a shallow repulsive Ξ^{-} interaction within pure neutron matter and this implies stiffer equations of state for neutron-rich matter including hyperons. Implications of the strong interaction for the modeling of neutron stars are discussed.

Magnetocaloric effects from an interplay of magnetic sublattices in Nd2NiMnO6

We present a combined experimental and theoretical study to understand the magnetism and magnetocaloric behavior of the double perovskite Nd₂NiMnO₆. The magnetic susceptibility data confirms a ferromagnetic transition with [Formula: see text] K. An additional feature at T  =  25 K, indicative of antiferromagnetic correlations, is present. A positive magnetocaloric effect (MCE) near [Formula: see text] and a negative MCE around T  =  25 K is inferred from the temperature dependence of the change in magnetic entropy at low magnetic fields. The negative MCE peak is suppressed on the application of a magnetic field and can be made to switch to a conventional positive MCE upon increasing magnetic field. We understand and reproduce these features in Monte Carlo simulations of a phenomenological Heisenberg model for Nd₂NiMnO₆. The validity of the model is tested using density functional theory calculations. We argue that this simple understanding of the experimental observations in terms of two antiferromagnetically coupled sublattices allows these results to be useful across a broader class of magnetocaloric materials.

Azimuthal Anisotropy of Heavy-Flavor Decay Electrons in p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

Angular correlations between heavy-flavor decay electrons and charged particles at midrapidity (|η|<0.8) are measured in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV. The analysis is carried out for the 0%-20% (high) and 60%-100% (low) multiplicity ranges. The jet contribution in the correlation distribution from high-multiplicity events is removed by subtracting the distribution from low-multiplicity events. An azimuthal modulation remains after removing the jet contribution, similar to previous observations in two-particle angular correlation measurements for light-flavor hadrons. A Fourier decomposition of the modulation results in a positive second-order coefficient (v_{2}) for heavy-flavor decay electrons in the transverse momentum interval 1.5<p_{T}<4  GeV/c in high-multiplicity events, with a significance larger than 5σ. The results are compared with those of charged particles at midrapidity and those of inclusive muons at forward rapidity. The v_{2} measurement of open heavy-flavor particles at midrapidity in small collision systems could provide crucial information to help interpret the anisotropies observed in such systems.

Abstract P3-10-18: Elucidating the role of functional signal transduction pathway activity in sensitivity and response of triple negative breast cancer to PI3K inhibition

Introduction

The PI3K signaling pathway is frequently active in triple negative breast cancer (TNBC), but response to PI3K inhibition is still poorly understood. To gain insights in therapy response and resistance, it is important not only to assess genetic alterations of these tumors, but also their phenotypic characteristics. Furthermore, not only is the functional status of the PI3K pathway important to know, but also other signal transduction pathways that may drive tumor growth, as they may explain primary or acquired therapy resistance.

Material & Method

We analyzed 17 patient derived xenograft (PDX) models of TNBC with varying response to buparlisib treatment. Long-term response (˜30 days) was assessed by comparing growth rates between buparlisib and vehicle treated PDXs. For characterization, mRNA expression analysis was performed on tumor material post 3 days of vehicle or buparlisib treatment of each PDX model. Functional pathway activity was determined using computational Bayesian networks that look at mRNA levels of pathway target genes resulting from activation (Verhaegh et al, Cancer Res 2014), amongst others for the FOXO-PI3K (van Ooijen et al, Am J Pathol, in press), ER, AR, Hedgehog, TGFbeta and Wnt pathways. These computational networks were calibrated on samples with known pathway activity, and biologically validated on various healthy and diseased cell and tissue types.

Results

On an initial set of 6 PDX models, pathway activity clearly varied between different TNBC PDXs, and between vehicle and buparlisib treatment. ER pathway activity was low in all samples, as expected in TNBC. Two PDX models with the most growth reduction by buparlisib showed high PI3K activity, of which one based on low FOXO activity and the other on oxidative stress. The former, best responding PDX showed a clear reduction in PI3K activity (restoring FOXO activity), when comparing 3 days buparlisib to vehicle treatment. Of the two PDX models with least growth reduction, one had low PI3K activity, while the other one, carrying a PIK3CA mutation, did show high PI3K activity (low FOXO), but this remained after treatment.

Other differences in pathway activity that were found, included slightly elevated AR and Wnt activity in one PDX with good response, and somewhat higher TGFbeta activity in four PDXs (good, medium and poor response). Analysis of the remaining 11 PDXs is ongoing, including other signal transduction pathways, to investigate the variation in pathway activity across the entire panel and to shed more light on the differences in tumor biology between the PDX models.

Conclusion

Our computational Bayesian networks measured differences in functional activity of signal transduction pathways across a collection of TNBC PDX models, which may be expected due to the large variation between TNBC tumors. Functional PI3K activity was related to growth inhibition by buparlisib treatment, and reduction of PI3K pathway activity was observed upon treatment in responding PDX models. Other pathways also showed variation across PDXs. Further clinical evaluation of our signal transduction pathway activity measurement is ongoing. RT-qPCR based analysis is available, optimized for FFPE tissue and small samples.

Citation Format: Guo Z, Verhaegh W, Hoog J, Rajput S, van Strijp D, van de Stolpe A, Li S, Ma C. Elucidating the role of functional signal transduction pathway activity in sensitivity and response of triple negative breast cancer to PI3K inhibition [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-10-18.

127 Temporal regulation of molecular pathways, metabolic enzymes and growth factor receptors during bovine oocyte maturation in vitro

Although great efforts have been made to improve in vitro oocyte maturation (IVM) medium, we have yet to achieve competence equivalent to in vivo-matured oocytes. The failure in development of culture conditions for IVM yielding high quality eggs is attributed to an incomplete understanding of molecular pathways regulating oocyte and cumulus cell metabolism. The objective of the present study was to characterise the expression and functional activity of cell signalling pathways (mTOR, AKT, 4EBP1, ERK1/2), metabolic enzymes (PKM2, PDH, LDHA, AMPK), and growth factor receptors (IGF1R, IGFIIR, EGFR, FGFR1) in bovine oocytes and cumulus cells before and after in vitro maturation. In vitro-derived cumulus-oocyte complexes were collected at germinal vesicle (GV) and metaphase II (MII) stages (20 cumulus-oocyte complexes per stage; n=3 replicates) and subjected separately to Western blot analysis using antibodies against both phosphorylated (p) and total (t) protein abundance; the ratio p:t was used to determine the activity of each pathway. Results demonstrate increased (P&lt;0.05) mTOR and ERK1/2 signalling, with no change in AKT and 4EBP1 activity, in oocytes during IVM. We observed increased (P&lt;0.05) abundance of oocyte t-ERK from the GV to MII stage, but total expression of AKT, mTOR and 4EBP1 did not change. In cumulus cells, there was a significant (P&lt;0.05) reduction in mTOR and 4EBP1, an increase in AKT, and no significant change in ERK activity. Analysis of metabolic enzymes in oocytes demonstrated increased (P&lt;0.05) PDH, reduced AMPK, and unchanged PKM2 and LDHA phosphorylation during IVM. However, increased expression of t-PKM2 abundance was observed from the GV to MII stage. In cumulus cells, tAMPK abundance was reduced (P&gt;0.05), but no significant change was observed in the activity of other metabolic enzymes analysed during IVM. Finally, we observed abundant expression of IGF2R in the oocyte compared with other growth factor receptors analysed, although IGF2R was significantly (P&lt;0.05) reduced from GV to MII oocytes. In cumulus cells, both IGF1R and IGF2R were highly abundant compared with EGFR and FGFR but did not change during IVM. Data were analysed using one-way ANOVA. Results suggest that regulatory mechanisms including AKT/mTOR/4EBP1 and ERK are entirely different in oocytes and cumulus cells during maturation. An increase in the inhibitory phosphorylation of oocyte PDH (S293) toward the end of maturation suggests low metabolism of pyruvate via the Krebs cycle at that time. Similarly, dephosphorylation of AMPK (T172) suggests reduced AMPK activity and reduced fatty acid oxidation in mature oocytes. In addition, temporal regulation of IGF1R in the oocyte and EGFR in cumulus cells suggests an important role for these growth factor receptors during maturation and that these growth factors could be used to improve IVM medium in the bovine. Collectively, these results increase our understanding of the molecular pathways regulating oocyte metabolism during maturation and provide a strategy to improve the IVM environment for assisted reproductive technology.

79 CRISPR gene editing in bovine zygotes — mutation confirmation by integration of protein expression and DNA sequencing analyses

Confirmation of gene editing in livestock following CRISPR/Cas9 zygotic microinjection is often limited to either protein expression or gene sequencing analyses of unfixed embryos, but not both, due to the challenges of extracting DNA from fixed samples suitable for genotyping. Bovine embryos have been derived from gene-edited cell lines to screen for mutations followed by nuclear transfer, but these techniques limit embryo production efficiency, include technical challenges, and alter physiological relevance. Herein we report an integrative approach to evaluate both protein expression and the genotype of individual, fixed bovine embryos subjected to CRISPR/Cas9 microinjection. Bovine zygotes were derived from IVF and parthenogenetic activation of in vitro-matured oocytes followed by intracytoplasmic injection of CRISPR/Cas9 targeting embryonic POU5F1. Embryos were cultured for 7 days and fixed in 4% paraformaldehyde and stored at 5°C for up to 4 weeks. Fixed embryos were first subjected to immunohistochemistry to determine POU5F1 mutation success by protein expression. Binder reinforcement labels were affixed to glass slides as a substitute for adhesive spacers. Single embryos were added to 9µL of PBS with a coverslip for imaging. Individual embryos were then recovered and placed in 10µL of QuickExtract (Lucigen, Middleton, WI, USA) for DNA extraction by heating samples to 65°C for 6min and 95°C for 2min. Two rounds of PCR were applied to templates in 20-µL reactions consisting of 10µL of GoTaq Hot Start Green Master Mix (2×; Promega, Madison, WI, USA) with the addition of 0.4µL (10µM) of forward and reverse primer each and 9.2µL of template. The second PCR reaction contained 5µL of PCR product from the first reaction, nested primers, and 4.2µL of H2O. The PCR conditions were |95°C, 3 min| and 35 cycles of |95°C, 30s |56°C, 30 s|72°C, 30 s|72°C, 7 min|. The PCR product was run on an agarose gel to confirm DNA amplification of a single band, and the remainder was purified (QIAquick PCR Purification Kit, Qiagen, Hilden, Germany) and submitted (100ng) for Sanger sequencing. The CRISPR-injected embryos were aligned to wild-type embryo sequences using SnapGene (http://www.snapgene.com/) and TIDE software (https://tide.nki.nl/). Both DNA extraction (n=18/19) and Sanger sequencing (n=19/23) proved highly efficient and repeatable (83 and 95%, respectively). These methods provide an efficient, cost effective, and reproducible approach for confirmation of CRISPR gene editing in individual and fixed bovine embryos by both protein expression and gene sequencing. In addition, these techniques complement the production of gene editing in livestock after zygotic CRISPR microinjection by conclusively determining mutation efficiency through both proteomic and genomic analyses. This research was supported by a USDA NIFA AFRI ELI Postdoctoral Fellowship 2016-67012-25254 to BWD and NIFA multistate research project W3171 to PJR. BD is currently supported by a grant from the Eunice Kennedy Shiver National Institute of Child Health and Human Development of the National Institutes of Health under the award numbers T32HD087166.

mTORC2 modulates the amplitude and duration of GFAT1 Ser-243 phosphorylation to maintain flux through the hexosamine pathway during starvation

The mechanistic target of rapamycin (mTOR) controls metabolic pathways in response to nutrients. Recently, we have shown that mTOR complex 2 (mTORC2) modulates the hexosamine biosynthetic pathway (HBP) by promoting the expression of the key enzyme of the HBP, glutamine:fructose-6-phosphate aminotransferase 1 (GFAT1). Here, we found that GFAT1 Ser-243 phosphorylation is also modulated in an mTORC2-dependent manner. In response to glutamine limitation, active mTORC2 prolongs the duration of Ser-243 phosphorylation, albeit at lower amplitude. Blocking glycolysis using 2-deoxyglucose robustly enhances Ser-243 phosphorylation, correlating with heightened mTORC2 activation, increased AMPK activity, and O-GlcNAcylation. However, when 2-deoxyglucose is combined with glutamine deprivation, GFAT1 Ser-243 phosphorylation and mTORC2 activation remain elevated, whereas AMPK activation and O-GlcNAcylation diminish. Phosphorylation at Ser-243 promotes GFAT1 expression and production of GFAT1-generated metabolites including ample production of the HBP end-product, UDP-GlcNAc, despite nutrient starvation. Hence, we propose that the mTORC2-mediated increase in GFAT1 Ser-243 phosphorylation promotes flux through the HBP to maintain production of UDP-GlcNAc when nutrients are limiting. Our findings provide insights on how the HBP is reprogrammed via mTORC2 in nutrient-addicted cancer cells.