HEBP2 affects sensitivity to cisplatin and BCNU but not to paclitaxel in MDA-MB-231 breast cancer cells.

Breast cancer has the highest incidence of all cancer types in women. Triple-negative breast cancer (TNBC) accounts for 15% of all breast cancer cases and is the most aggressive type, with a poor prognosis and limited treatment. Treatment failure in patients is largely due to resistance to chemotherapy. In this study, we aimed to identify the novel factors contributing to chemoresistance in TNBC using cisplatin and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). We found that transactivation of the heme-binding protein 2 (HEBP2) gene was common in surviving colonies of cells after exposure to two types of chemotherapeutic agents, namely cisplatin and BCNU, from genome-scale transcriptional activation library screening in the TNBC cell line MDA-MB-231. Analysis of a public database (Proteogenomic Landscape of Breast Cancer, CPTAC) indicated that HEBP2 mRNA expression was elevated in TNBC tissues compared to that in non-TNBC tissues. HEBP2 facilitates necrotic cell death under oxidative stress; however, it is not yet known whether HEBP2 affects cancer cell survival following chemotherapy. Therefore, we investigated the effects of HEBP2 expression on the sensitivity to cisplatin and BCNU in MDA-MB-231 cells. Overexpression of HEBP2 significantly enhanced the viability of MDA-MB-231 cells in response to cisplatin and BCNU, but not methyl methanesulfonate (MMS) and paclitaxel. In contrast, CRISPR/Cas9-mediated HEBP2-knockout greatly reduced cell viability in response to cisplatin and BCNU, but not to MMS and paclitaxel, in MDA-MB-231 cells. Moreover, the exogenous introduction of HEBP2 restored the resistance of HEBP2-deficient cells to cisplatin and BCNU to wild-type levels. These findings suggest that HEBP2 may play a significant role in resistance to cisplatin and BCNU, which induce intrastrand and interstrand DNA crosslinks, but not to monoalkylating or microtubule-stabilizing agents in TNBC cells. The possibility exists that HEBP2 serves as a biomarker for predicting response or a therapeutic target for overcoming resistance to platinum-based and alkylating anticancer agents in TNBC.

PARIS undergoes liquid-liquid phase separation and poly(ADP-ribose)-mediated solidification.

ZNF746 was identified as parkin-interacting substrate (PARIS). Investigating its pathophysiological properties, we find that PARIS undergoes liquid-liquid phase separation (LLPS) and amorphous solid formation. The N-terminal low complexity domain 1 (LCD1) of PARIS is required for LLPS, whereas the C-terminal prion-like domain (PrLD) drives the transition from liquid to solid phase. In addition, we observe that poly(ADP-ribose) (PAR) strongly binds to the C-terminus of PARIS near the PrLD, accelerating its LLPS and solidification. N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced PAR formation leads to PARIS oligomerization in human iPSC-derived dopaminergic neurons that is prevented by the PARP inhibitor, ABT-888. Furthermore, SDS-resistant PARIS species are observed in the substantia nigra (SN) of aged mice overexpressing wild-type PARIS, but not with a PAR binding-deficient PARIS mutant. PARIS solidification is also found in the SN of mice injected with preformed fibrils of α-synuclein (α-syn PFF) and adult mice with a conditional knockout (KO) of parkin, but not if α-syn PFF is injected into mice deficient for PARP1. Herein, we demonstrate that PARIS undergoes LLPS and PAR-mediated solidification in models of Parkinson's disease.

Inoculation of ACC deaminase-producing endophytic bacteria down-regulates ethylene-induced pathogenesis-related signaling in red pepper (Capsicum annuum L.) under salt stress.

Pathogenesis-related (PR) signaling plays multiple roles in plant development under abiotic and biotic stress conditions and is regulated by a plethora of plant physiological as well as external factors. Here, our study was conducted to evaluate the role of an ACC deaminase-producing endophytic bacteria in regulating ethylene-induced PR signaling in red pepper plants under salt stress. We also evaluated the efficiency of the bacteria in down-regulating the PR signaling for efficient colonization and persistence in the plant endosphere. We used a characteristic endophyte, Methylobacterium oryzae CBMB20 and its ACC deaminase knockdown mutant (acdS- ). The wild-type M. oryzae CBMB20 was able to decrease ethylene emission by 23% compared to the noninoculated and acdS- M. oryzae CBMB20 inoculated plants under salt stress. The increase in ethylene emission resulted in enhanced hydrogen peroxide concentration, phenylalanine ammonia-lyase activity, ß-1,3 glucanase activity, and expression profiles of WRKY, CaPR1, and CaPTI1 genes that are typical salt stress and PR signaling factors. Furthermore, the inoculation of both the bacterial strains had shown induction of PR signaling under normal conditions during the initial inoculation period. However, wild-type M. oryzae CBMB20 was able to down-regulate the ethylene-induced PR signaling under salt stress and enhance plant growth and stress tolerance. Collectively, ACC deaminase-producing endophytic bacteria down-regulate the salt stress-mediated PR signaling in plants by regulating the stress ethylene emission levels and this suggests a new paradigm in efficient colonization and persistence of ACC deaminase-producing endophytic bacteria for better plant growth and productivity.

Identification of Three Human POLH Germline Variants Defective in Complementing the UV- and Cisplatin-Sensitivity of POLH-Deficient Cells.

DNA polymerase (pol) η is responsible for error-free translesion DNA synthesis (TLS) opposite ultraviolet light (UV)-induced cis-syn cyclobutane thymine dimers (CTDs) and cisplatin-induced intrastrand guanine crosslinks. POLH deficiency causes one form of the skin cancer-prone disease xeroderma pigmentosum variant (XPV) and cisplatin sensitivity, but the functional impacts of its germline variants remain unclear. We evaluated the functional properties of eight human POLH germline in silico-predicted deleterious missense variants, using biochemical and cell-based assays. In enzymatic assays, utilizing recombinant pol η (residues 1-432) proteins, the C34W, I147N, and R167Q variants showed 4- to 14-fold and 3- to 5-fold decreases in specificity constants (kcat/Km) for dATP insertion opposite the 3'-T and 5'-T of a CTD, respectively, compared to the wild-type, while the other variants displayed 2- to 4-fold increases. A CRISPR/Cas9-mediated POLH knockout increased the sensitivity of human embryonic kidney 293 cells to UV and cisplatin, which was fully reversed by ectopic expression of wild-type pol η, but not by that of an inactive (D115A/E116A) or either of two XPV-pathogenic (R93P and G263V) mutants. Ectopic expression of the C34W, I147N, and R167Q variants, unlike the other variants, did not rescue the UV- and cisplatin-sensitivity in POLH-knockout cells. Our results indicate that the C34W, I147N, and R167Q variants-substantially reduced in TLS activity-failed to rescue the UV- and cisplatin-sensitive phenotype of POLH-deficient cells, which also raises the possibility that such hypoactive germline POLH variants may increase the individual susceptibility to UV irradiation and cisplatin chemotherapy.

Distinctive optical transitions of tunable multicolor carbon dots.

Three types of carbon dots (CDs) are synthesized from isomers of phenylenediamine to develop multicolor nanomaterials with low toxicity, high stability, and high quantum yield. The distinctive electronic structures of CDs lead to the characteristic optical transitions, such as three colors of blue, green, and red, which are primarily attributed to the difference in configurations, despite the similar basic structures of conjugated systems. The excitation-independent emission and the single exponential decay of CDs indicate the single chromophore-like nature in each type of CD. In addition, the two-photon luminescence of CDs exhibits a comparable shape and time profile to the typical photoluminescence with high photostability. Although the surface-related defect states are observed by intragap excitation, the contribution of defect states is barely observed in the emission profile upon band gap excitation. Consequently, the controllability of optical transitions in CDs enhances the potential of tunable multicolor nanomaterials for various applications as alternatives to quantum dots containing toxic elements.

Enhanced near-infrared electrochemiluminescence of Au nanoclusters treated with piperidine.

Au nanoclusters (NCs) are considered a promising electrochemiluminescence (ECL) luminophore with biocompatibility and stability that make it suitable for use in bioelectrochemical investigations. The near-infrared (near-IR) ECL of Au NCs is of particular interest for biological applications. In this study, we report the significantly enhanced near-IR ECL of water-soluble Au NCs stabilized with glutathione, which was induced by treating the Au NCs with piperidine. The piperidine treatment of Au NCs enabled a 16-fold enhancement in the near-IR ECL of the NCs in the presence of triethylamine coreactants in water. Compared to the well-known near-IR ECL of Au NCs stabilized with bovine serum albumin (BSA) as a control, the near-IR ECL emission of the piperidine-treated Au NCs (p-Au NCs) was 8 times that of the BSA-stabilized Au NCs. Detailed control experiments suggested that the enhanced near-IR ECL of p-Au NCs could be attributed not to environmental effects (e.g., pH and chemical interference) and the surface ligand effect, but to the reduction of Au(I)-glutathione to Au(0)-glutathione in the NCs. Importantly, the piperidine treatment was also shown to be applicable to different types of Au NCs, such as well-established Au22(SG)18, for improving the ECL emission of the NCs in the near-IR region.

Label-free proteomics approach reveals candidate proteins in rice (Oryza sativa L.) important for ACC deaminase producing bacteria-mediated tolerance against salt stress.

The omics-based studies are important for identifying characteristic proteins in plants to elucidate the mechanism of ACC deaminase producing bacteria-mediated salt tolerance. This study evaluates the changes in the proteome of rice inoculated with ACC deaminase producing bacteria under salt-stress conditions. Salt stress resulted in a significant decrease in photosynthetic pigments, whereas inoculation of Methylobacterium oryzae CBMB20 had significantly increased pigment contents under normal and salt-stress conditions. A total of 76, 51 and 33 differentially abundant proteins (DAPs) were identified in non-inoculated salt-stressed plants, bacteria-inoculated plants under normal and salt stress conditions respectively. The abundances of proteins responsible for ethylene emission and programmed cell death were increased, and that of photosynthesis-related proteins were decreased in non-inoculated plants under salt stress. However, bacteria-inoculated plants had shown higher abundance of antioxidant proteins, RuBisCo and ribosomal proteins that are important for enhancing stress tolerance and improving plant physiological traits. Collectively, salt stress might affect plant physiological traits by impairing photosynthetic machinery and accelerating apoptosis leading to a decline in biomass. However, inoculation of plants with bacteria can assist in enhancing photosynthetic activity, antioxidant activities and ethylene regulation related proteins for attenuating salt-induced apoptosis and sustaining growth and development.

ACC deaminase-producing Brevibacterium linens RS16 enhances heat-stress tolerance of rice (Oryza sativa L.).

The rapid rise in global temperature has adverse effects on rice productivity. The lack of eminent resources for heat stress alleviation is threatening the agricultural sector. Heat stress alleviation by endophytic plant growth-promoting bacteria (PGPB) can be a sustainable and eco-friendly approach. The present study was conducted to check the colonization of Brevibacterium linens RS16 producing ACC (1-aminocyclopropane-1-carboxylate) deaminase in the rice endosphere and to characterize its efficiency in enhancing stress tolerance. The ethylene emission pathway, reactive oxygen species (ROS) concentrations, proline accumulation, expression of glutathione S-transferase (GST), and small heat shock proteins (sHSPs) were monitored at two different levels of heat stress (40°C and 45°C). Bacterial inoculation decreased ethylene emission levels by 26.9% and 24.4% in rice plants exposed to 40°C and 45°C, respectively, compared with the non-inoculated plants. B. linens RS16 also enhanced the expression profiles of glutathione S-transferase. The collective effect of GST expression profiles and decrease in ethylene emission due to bacterial ACC deaminase activity subsequently resulted in a decrease in ROS concentrations. Additionally, HSP16 and HSP26 increased expression in heat-stressed plants inoculated with B. linens RS16 resulted in enhanced stress tolerance (i.e., lesser proline accumulation) than non-inoculated plants. Hence, this study demonstrates the bacteria-mediated tolerance against heat stress by regulating the ethylene emission pathway and upregulating antioxidant enzymes and heat shock proteins.

Exposure to Oxy-Tetracycline Changes Gut Bacterial Community Composition in Rainbow Trout: A Preliminary Study.

The extensive use of antibiotics is evident in most of the livestock and aquaculture management for inhibiting pathogen infection. Korean aquaculture depends on the usage of oxy-tetracycline for growing rainbow trout. Hence, this study was conducted to evaluate the changes in gut bacterial community profiles of rainbow trout exposed to oxy-tetracycline and predict the metabolic functioning of the bacterial community. The gut bacterial community composition of oxy-tetracycline treated fish was assessed by amplicon sequencing targeting the 16S rRNA gene of bacteria and comparing with the control group that did not receive any antibiotic. The principle coordinate analysis and non-metric multidimensional scaling analysis had shown two distinct clusters that implies the changes in community composition. In phyla level, the relative abundances of Tenericutes and Firmicutes were observed to be significantly higher in oxy-tetracycline treated fish compared to the control. Furthermore, the prediction based metabolic profiling revealed the processes that are affected due to the shift in community profiles. For example, metabolic functioning of membrane efflux system, amino acid metabolism and glycolysis were significantly higher in oxy-tetracycline treated fish compared to the control. This study describes alteration in gut bacterial community composition and potential metabolic profiles of the community that might be responsible for surviving in antibiotic rich environment.

Loss of zinc-finger protein 212 leads to Purkinje cell death and locomotive abnormalities with phospholipase D3 downregulation.

Although Krüppel-associated box domain-containing zinc-finger proteins (K-ZNFs) may be associated with sophisticated gene regulation in higher organisms, the physiological functions of most K-ZNFs remain unknown. The Zfp212 protein was highly conserved in mammals and abundant in the brain; it was mainly expressed in the cerebellum (Cb). Zfp212 (mouse homolog of human ZNF212) knockout (Zfp212-KO) mice showed a reduction in survival rate compared to wild-type mice after 20 months of age. GABAergic Purkinje cell degeneration in the Cb and aberrant locomotion were observed in adult Zfp212-KO mice. To identify genes related to the ataxia-like phenotype of Zfp212-KO mice, 39 ataxia-associated genes in the Cb were monitored. Substantial alterations in the expression of ataxin 10, protein phosphatase 2 regulatory subunit beta, protein kinase C gamma, and phospholipase D3 (Pld3) were observed. Among them, Pld3 alone was tightly regulated by Flag-tagged ZNF212 overexpression or Zfp212 knockdown in the HT22 cell line. The Cyclic Amplification and Selection of Targets assay identified the TATTTC sequence as a recognition motif of ZNF212, and these motifs occurred in both human and mouse PLD3 gene promoters. Adeno-associated virus-mediated introduction of human ZNF212 into the Cb of 3-week-old Zfp212-KO mice prevented Purkinje cell death and motor behavioral deficits. We confirmed the reduction of Zfp212 and Pld3 in the Cb of an alcohol-induced cerebellar degeneration mouse model, suggesting that the ZNF212-PLD3 relationship is important for Purkinje cell survival.