Insights into pollution characteristics and human health risks of plasticizer phthalate esters in shellfish species.

The ubiquitous application of phthalate esters (PAEs) as plasticizers contributes to high levels of marine pollution, yet the contamination patterns of PAEs in various shellfish species remain unknown. The objective of this research is to provide the first information on the pollution characteristics of 16 PAEs in different shellfish species from the Pearl River Delta (PRD), South China, and associated health risks. Among the 16 analyzed PAEs, 13 were identified in the shellfish, with total PAE concentrations ranging from 23.07 to 3794.08 ng/g dw (mean = 514.35 ng/g dw). The PAE pollution levels in the five shellfish species were as follows: Ostreidae (mean = 1064.12 ng/g dw) > Mytilus edulis (mean = 509.88 ng/g dw) > Babylonia areolate (mean = 458.14 ng/g dw) > Mactra chinensis (mean = 378.90 ng/g dw) > Haliotis diversicolor (mean = 335.28 ng/g dw). Dimethyl phthalate (DMP, mean = 69.85 ng/g dw), diisobutyl phthalate (DIBP, mean = 41.39 ng/g dw), dibutyl phthalate (DBP, mean = 130.91 ng/g dw), and di(2-ethylhexyl) phthalate (DEHP, mean = 226.23 ng/g dw) were the most abundant congeners. Notably, DEHP constituted the most predominant fraction (43.98 %) of the 13 PAEs detected in all shellfish from the PRD. Principal component analysis indicated that industrial and domestic emissions served as main sources for the PAE pollution in shellfish from the PRD. It was estimated that the daily intake of PAEs via shellfish consumption among adults and children ranged from 0.004 to 1.27 µg/kgbw/day, without obvious non-cancer risks (< 0.034), but the cancer risks raised some alarm (2.0 × 10-9-1.4 × 10-5). These findings highlight the necessity of focusing on marine environmental pollutants and emphasize the importance of ongoing monitoring of PAE contamination in seafood.

Ecologically different earthworm species are the driving force of microbial hotspots influencing Pb uptake by the leafy vegetable Brassica campestris.

Food chain contamination by soil lead (Pb), beginning with Pb uptake by leafy vegetables, is a threat to food safety and poses a potential risk to human health. This study highlights the importance of two ecologically different earthworm species (the anecic species Amynthas aspergillum and the epigeic species Eisenia fetida) as the driving force of microbial hotspots to enhance Pb accumulation in the leafy vegetable Brassica campestris at different Pb contamination levels (0, 100, 500, and 1,000 mg·kg-1). The fingerprints of phospholipid fatty acids (PLFAs) were employed to reveal the microbial mechanism of Pb accumulation involving earthworm-plant interaction, as PLFAs provide a general profile of soil microbial biomass and community structure. The results showed that Gram-positive (G+) bacteria dominated the microbial community. At 0 mg·kg-1 Pb, the presence of earthworms significantly reduced the total PLFAs. The maximum total of PLFAs was found at 100 mg·kg-1 Pb with E. fetida inoculation. A significant shift in the bacterial community was observed in the treatments with E. fetida inoculation at 500 and 1,000 mg·kg-1 Pb, where the G+/G- bacteria ratio was significantly decreased compared to no earthworm inoculation. Principal component analysis (PCA) showed that E. fetida had a greater effect on soil microbial hotspots than A. aspergillum, thus having a greater effect on the Pb uptake by B. campestris. Redundancy analysis (RDA) showed that soil microbial biomass and structure explained 43.0% (R2 = 0.53) of the total variation in Pb uptake by B. campestris, compared to 9.51% of microbial activity. G- bacteria explained 23.2% of the total variation in the Pb uptake by B. campestris, significantly higher than the other microbes. The Mantel test showed that microbial properties significantly influenced Pb uptake by B. campestris under the driving force of earthworms. E. fetida inoculation was favorable for the G- bacterial community, whereas A. aspergillum inoculation was favorable for the fungal community. Both microbial communities facilitated the entry of Pb into the vegetable food chain system. This study delivers novel evidence and meaningful insights into how earthworms prime the microbial mechanism of Pb uptake by leafy vegetables by influencing soil microbial biomass and community composition. Comprehensive metagenomics analysis can be employed in future studies to identify the microbial strains promoting Pb migration and develop effective strategies to mitigate Pb contamination in food chains.

Occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) in marine organisms from Shenzhen coastal waters and human health risk assessment.

This study investigated the levels and composition of 16 priority polycyclic aromatic hydrocarbons (PAHs) in marine organisms from South China Sea and assessed their potential health risks. The results revealed that the pollution levels of total PAHs ranged from 3.56 to 392.21 ng/g dw. Notably, 4-ring PAHs constituted the predominant fraction (58.02 %) of the total PAHs, with pyrene being the most abundant congener across all species. Intriguingly, our findings suggested that consuming these organisms might pose a low non-cancer hazard. Nonetheless, benzo[a]pyrene was detected in most species, with levels ranging from non-detectable to 11.24 ng/g dw. The individual lifetime cancer risk levels associated with seafood consumption in studied regions ranged from 1.10 × 10-5 to 1.52 × 10-5, highlighting a potential cancer risk that warrants special attention. These findings emphasize the need to prioritize carcinogenic compounds over total PAHs and underscore the importance of continuous monitoring of PAH pollution in seafood.

Application of improved Glasgow coma scale score as switching point for sequential invasive-noninvasive mechanical ventilation on chronic obstructive pulmonary disease (COPD) with respiratory failure.

BACKGROUND: To compare the efficacy and feasibility of using a modified Glasgow coma scale (GCS) score of 13 or 15 as the criterion for switching chronic obstructive pulmonary disease (COPD) patients with respiratory failure to sequential invasive-noninvasive ventilation. METHODS: COPD patients with respiratory failure who had undergone endotracheal intubation and invasive mechanical ventilation (IMV) between June 2017 and June 2020 at 4 different hospitals in China were included. A total of 296 patients were randomly divided into 2 groups. In group A, the patients were extubated and immediately placed on noninvasive ventilation (NIV) when the modified GCS score reached 13. In group B, the same was done when the modified GCS score reached 15. RESULTS: No significant differences in the mean blood pressure, oxygenation index, arterial partial pressure of oxygen, and arterial partial pressure of carbon dioxide were seen between groups A and B before extubation and 3 hours after NIV. The re-intubation times were also similar in the 2 groups. Compared to group B, the length of hospital stay, incidence of ventilator associated pneumonia, and time of invasive ventilation were all significantly lower in group A (P = .041, .001, <.001). CONCLUSION: Using a modified GCS score of 13 as the criterion for switching from IMV to NIV can significantly reduce the duration of IMV, length of hospital stay, and incidence of ventilator associated pneumonia in COPD patients with respiratory failure.

Evaluation of maize/peanut intercropping effects on microbial assembly, root exudates and peanut nitrogen uptake.

Legume/cereal intercropping has been widely studied within ecosystem function, owing to its overyield potential, predominantly by dinitrogen (N2) fixation. In our 2-year peanut/maize intercropping field experiment, land equivalent ratio (LER) showed an average yield-increase by 41.48%. Performance index of intercropped peanut (IP) functional leaves exhibited significant improvement (2.02-fold). Moreover, IP increased dry nodule weight by 58.82% as compared to mono-cropped. Also, the ratio of nodules to aboveground biomass in IP reduced by 65.8%. In pot experiment, higher urease activity was found in rhizosphere (22.73%). The abundance of Rhizobium and niƒH gene in the rhizosphere of IP were significantly enhanced by 71.91% and 208%, respectively. To analyze root exudates, we performed hydroponic coculture, the proportion of total isoflavonoids in peanut root exudates were increased distinctly by 22.4%. Our findings certainly helped in filling one the information gaps, that how intercropping increases nitrogen fixation in rhizosphere. Lastly, it can further facilitate to understand functional significance of intercropping system for agricultural ecological sustainability and efficient resource utilization.

Normalization of C-Reactive Protein Predicts Better Outcome in Patients With Crohn's Disease With Mucosal Healing and Deep Remission.

OBJECTIVES: Therapeutic targets for Crohn's disease (CD) have evolved from clinical and biological remission to mucosal healing (MH) and deep remission (DR). MH is defined as disappearance of ulceration, whereas DR is defined as a combination of clinical remission and MH. Limited data are available regarding differences in long-term outcomes of these patients reaching these targets. We thus aimed to evaluate patients' long-term clinical outcomes using different composite remission parameters. METHODS: We performed a retrospective cohort study comparing long-term outcomes of patients with different remission parameters, including MH and DR with or without normalization of C-reactive protein (CRPnorm). The primary outcome was CD-associated intestinal surgery, and secondary outcomes included CD-related hospitalizations, clinical relapse (CR), or endoscopic recurrence (ER). RESULTS: One hundred ninety-five patients with MH at follow-up endoscopy were divided into 3 groups: DR-only (n = 53), DR + CRPnorm (n = 106), and MH-only (n = 36). At the follow-up (median 46.0 months), 25 patients had undergone CD-related bowel surgery, 44 had CD-related hospitalizations, and 66 experienced CR. Of 151 patients who underwent follow-up colonoscopy after the index colonoscopy for MH, 96 experienced ER. Among the 3 groups, patients in the DR + CRPnorm group had the lowest risk of clinical or endoscopic relapse. The DR group had a lower rate of CR than the MH-only group (P = 0.03); there was no difference in the rate of CD-related surgery, hospitalizations, or ER. DISCUSSION: Patients with DR combined with a normalized CRP showed better outcomes than those with DR only. The outcomes of patients with MH were similar to those of patients with DR, except for shorter flare-free survival.

Comparative efficacy evaluation of inverted internal limiting membrane flap technique and internal limiting membrane peeling in large macular holes: a systematic review and meta-analysis.

BACKGROUND: The purpose of this study was to compare the anatomical and visual outcomes of inverted internal limiting membrane (ILM) flap technique and internal limiting membrane peeling in large macular holes (MH). METHODS: Related studies were reviewed by searching electronic databases of Pubmed, Embase, Cochrane Library. We searched for articles that compared inverted ILM flap technique with ILM peeling for large MH (> 400 µm). Double-arm meta-analysis was performed for the primary end point that was the rate of MH closure, and the secondary end point was postoperative visual acuity (VA). Heterogeneity, publication bias, sensitivity analysis and subgroup analysis were conducted to guarantee the statistical power. RESULTS: This review included eight studies involving 593 eyes, 4 randomized control trials and 4 retrospective studies. After sensitivity analysis for eliminating the heterogeneity of primary outcome, the pooled data showed the rate of MH closure with inverted ILM flap technique group was statistically significantly higher than ILM peeling group (odds ratio (OR) = 3.95, 95% confidence interval (CI) = 1.89 to 8.27; P = 0.0003). At the follow-up duration of 3 months, postoperative VA was significantly better in the group of inverted ILM flap than ILM peeling (mean difference (MD) = - 0.16, 95% CI = - 0.23 to 0.09; P < 0.00001). However, there was no difference in visual outcomes between the two groups of different surgical treatments at relatively long-term follow-up over 6 months (MD = 0.01, 95% CI = - 0.12 to 0.15; P = 0.86). CONCLUSION: Vitrectomy with inverted ILM flap technique had a better anatomical outcome than ILM peeling. Flap technique also had a signifcant visual gain in the short term, but the limitations in visual recovery at a longer follow-up was found.

Development of a novel TLR8 agonist for cancer immunotherapy.

Toll-like receptors (TLRs) are a family of proteins that recognize pathogen associated molecular patterns (PAMPs). Their primary function is to activate innate immune responses while also involved in facilitating adaptive immune responses. Different TLRs exert distinct functions by activating varied immune cascades. Several TLRs are being pursued as cancer drug targets. We discovered a novel, highly potent and selective small molecule TLR8 agonist DN052. DN052 exhibited strong in vitro cellular activity with EC50 at 6.7 nM and was highly selective for TLR8 over other TLRs including TLR4, 7 and 9. DN052 displayed excellent in vitro ADMET and in vivo PK profiles. DN052 potently inhibited tumor growth as a single agent. Moreover, combination of DN052 with the immune checkpoint inhibitor, selected targeted therapeutics or chemotherapeutic drugs further enhanced efficacy of single agents. Mechanistically, treatment with DN052 resulted in strong induction of pro-inflammatory cytokines in ex vivo human PBMC assay and in vivo monkey study. GLP toxicity studies in rats and monkeys demonstrated favorable safety profile. This led to the advancement of DN052 into phase 1 clinical trials.

Nerve growth factor promotes the proliferation of Müller cells co-cultured with internal limiting membrane by regulating cell cycle via Trk-A/PI3K/Akt pathway.

BACKGROUND: Nerve growth factor (NGF), produced by Müller cells, and internal limiting membrane (ILM) have fundamental roles in the development of full-thickness macular hole (FTMH). However, the potential crosstalk between NGF and ILM in FTMH is unclear. This study aimed to explore the mechanism and effects of NGF on the proliferation of Müller cells co-cultured with ILM. METHODS: Primary Müller cells and ILM from New Zealand rabbits were extracted and authenticated with specific staining. Müller cells co-cultured with or without ILM were exposed to NGF and then analysed. Müller cell viability was estimated using cell counting kit-8. Cell cycle analysis was performed by flow cytometry. The levels of cell cycle-related gene were detected using qRT-PCR. The TrK-A/Akt signal axis and downstream signaling cascades such as p21, CyclinE, CDK2, CyclinD1, and CDK4 were investigated by western blotting. RESULTS: ILM treatment alone induced the proliferation of Müller cells following the promotion of phosphorylated Akt, while growth of Müller cells was enhanced by activation of the Trk-A/Akt pathway under the stimulation of NGF or NGF + ILM. Additionally, the ratio of S-phase cells was increased, while G2-phase cells decreased upon the treatment with either ILM or NGF alone, or with NGF + ILM co-treatment. Cell cycle-related genes such as CyclinD1, CyclinE, CDK2, and CDK4 were all upregulated, but p21 expression was downregulated in the presence of NGF, ILM, or NGF + ILM. There was an additive effect on cell proliferation and cell cycle in the group of Müller cells exposed to NGF co-cultured with ILM compared with either NGF or ILM treatment alone. However, both K252ɑ (inhibitors of Trk-A) and LY294002 (inhibitor for Akt) counteracted the effect of NGF or NGF + ILM on the protein levels of Trk-A, Akt, CyclinD1, CyclinE, CDK2, and p21. CONCLUSIONS: Müller cells co-cultured with ILM or NGF promoted cell proliferation by regulating cell cycle-correlated proteins via the PI3K/Akt pathway. ILM + NGF further amplified the PI3K/Akt signaling pathway by binding to Trk-A, leading to more cell growth. This study provides new insight into the potential mechanism of NGF-mediated proliferation of Müller cells co-cultured with or without ILM, which may have considerable impact on therapies for FTMH.

Transdifferentiation effects and related mechanisms of nerve growth factor and internal limiting membrane on Müller cells.

In this study, we investigated the pro-proliferative, pro-transdifferentiation effects and mechanisms of nerve growth factor (NGF), internal limiting membrane (ILM), and NGF+ILM on Müller cells. The Müller cells cultured with NGF, ILM or both were mediated with tyrosine kinase A (TrkA) (a high affinity receptor for NGF) inhibitor, phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) (an intracellular signaling pathway important in regulating the cell cycle) inhibitor, or LIN28 (a RNA-binding protein and a posttranscriptional regulator of genes involved in developmental timing and self-renewal in embryonic stem cells) siRNA. Immunofluorescence (IF), western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) were performed to detect the expression of related genes. As a result, NGF, ILM and NGF+ILM promoted cell proliferation, increased the ratio of 5-bromo-2-deoxyuridine (BrdU)-positive cells, and were correlated with TrkA and PI3K/Akt signaling. NGF alone promoted cell dedifferentiation and redifferentiation mainly towards neurons rather than towards glial cells, related to TrkA and PI3K/Akt signals. The expression of p-Akt and cyclinD1 was increased by the intervention of NGF, ILM or NGF+ILM via TrkA and PI3K/Akt signals. NGF alone promoted the expression of paired box 6 (PAX6) (a transcription factor present during embryonic development), sex-determining region Y-box 2 (SOX2) (a transcription factor essential for the self-renewal, or pluripotency, of undifferentiated embryonic stem cells) and LIN28, and inhibited the expression of lethal-7 (Let-7b), Let-7d, Let-7i and miR-98 (microRNAs, key developmental regulators). The expression of Achaete-scute homolog 1 (Ascl1, also called MASH1) (a neurodevelopmental gene) and endogenous NGF (closely related to neurogenesis) was also promoted by exogenous NGF and related to TrkA and PI3K/Akt signaling. The down-regulation of LIN28 significantly antagonized the effects of NGF on the transdifferentiation of Müller cells. Over all, our results showed that NGF promoted the proliferation and transdifferentiation of Müller cells towards photoreceptor neurons--not towards glial cells, which was related to the LIN28/Let-7 pathway through TrkA and PI3K/Akt signals. Additionally, ILM promoted Müller cells to enter the cell cycle and enhanced cell proliferation, since NGF+ILM promoted the proliferation of Müller cell more significantly than NGF alone.

Identification of Aeromonas hydrophila Genes Preferentially Expressed after Phagocytosis by Tetrahymena and Involvement of Methionine Sulfoxide Reductases.

Free-living protozoa affect the survival and virulence evolution of pathogens in the environment. In this study, we explored the fate of Aeromonas hydrophila when co-cultured with the bacteriovorous ciliate Tetrahymena thermophila and investigated bacterial gene expression associated with the co-culture. Virulent A. hydrophila strains were found to have ability to evade digestion in the vacuoles of this protozoan. In A. hydrophila, a total of 116 genes were identified as up-regulated following co-culture with T. thermophila by selective capture of transcribed sequences (SCOTS) and comparative dot-blot analysis. A large proportion of these genes (42/116) play a role in metabolism, and some of the genes have previously been characterized as required for bacterial survival and replication within macrophages. Then, we inactivated the genes encoding methionine sulfoxide reductases, msrA, and msrB, in A. hydrophila. Compared to the wild-type, the mutants ΔmsrA and ΔmsrAB displayed significantly reduced resistance to predation by T. thermophila, and 50% lethal dose (LD50) determinations in zebrafish demonstrated that both mutants were highly attenuated. This study forms a solid foundation for the study of mechanisms and implications of bacterial defenses.

Acid tolerance response (ATR) of microbial communities during the enhanced biohydrogen process via cascade acid stress.

Enhanced biohydrogen production via cascade acid stress on microbial communities, structure patterns of the microbial communities revealed by PLFAs, and the succession of biohydrogen related species against cascade acid stress were all investigated. It was found that hydrogen production could be improved from 48.7 to 79.4mL/gVS after cascade acid stress. In addition, the Gram negative (G(-)) bacteria were found to be more tolerant to organic acids than those of the Gram positive (G(+)) bacteria, regardless of the dominance of G(+) bacteria within the microbial communities. Moreover, Clostridium butyricum, Clostridium aciditolerans and Azospira oryzae, were proved to be enriched, and then might play indispensable roles for the enhanced biohydrogen production after cascade acid stress, as which were responsible for the biohydrogen accumulation, acid tolerance and nitrogen removal, respectively.

A novel small molecule RAD51 inactivator overcomes imatinib-resistance in chronic myeloid leukaemia.

RAD51 recombinase activity plays a critical role for cancer cell proliferation and survival, and often contributes to drug-resistance. Abnormally elevated RAD51 function and hyperactive homologous recombination (HR) rates have been found in a panel of cancers, including breast cancer and chronic myeloid leukaemia (CML). Directly targeting RAD51 and attenuating the deregulated RAD51 activity has therefore been proposed as an alternative and supplementary strategy for cancer treatment. Here we show that a newly identified small molecule, IBR2, disrupts RAD51 multimerization, accelerates proteasome-mediated RAD51 protein degradation, reduces ionizing radiation-induced RAD51 foci formation, impairs HR, inhibits cancer cell growth and induces apoptosis. In a murine imatinib-resistant CML model bearing the T315I Bcr-abl mutation, IBR2, but not imatinib, significantly prolonged animal survival. Moreover, IBR2 effectively inhibits the proliferation of CD34(+) progenitor cells from CML patients resistant to known BCR-ABL inhibitors. Therefore, small molecule inhibitors of RAD51 may suggest a novel class of broad-spectrum therapeutics for difficult-to-treat cancers.

Tetrahymena: an alternative model host for evaluating virulence of Aeromonas strains.

An easier assessment model would be helpful for high-throughput screening of Aeromonas virulence. The previous study indicated the potential of Tetrahymena as a permissive model to examine virulence of Aeromonas hydrophila. Here our aim was to assess virulence of Aeromonas spp. using two model hosts, a zebrafish assay and Tetrahymena-Aeromonas co-culture, and to examine whether data from the Tetrahymena thermophila model reflects infections in the well-established animal model. First, virulence of 39 Aeromonas strains was assessed by determining the 50% lethal dose (LD(50)) in zebrafish. LD(50) values ranging from 1.3×10(2) to 3.0×10(7) indicated that these strains represent a high to moderate degree of virulence and could be useful to assess virulence in the Tetrahymena model. In Tetrahymena-Aeromonas co-culture, we evaluated the virulence of Aeromonas by detecting relative survival of Aeromonas and Tetrahymena. An Aeromonas isolate was considered virulent when its relative survival was greater than 60%, while the Aeromonas isolate was considered avirulent if its relative survival was below 40%. When relative survival of T. thermophila was lower than 40% after co-culture with an Aeromonas isolate, the bacterial strain was regarded as virulent. In contrast, the strain was classified as avirulent if relative survival of T. thermophila was greater than 50%. Encouragingly, data from the 39 Aeromonas strains showed good correlation in zebrafish and Tetrahymena-Aeromonas co-culture models. The results provide sufficient data to demonstrate that Tetrahymena can be a comparable alternative to zebrafish for determining the virulence of Aeromonas isolates.

Cloning and distribution of neuropeptide S and its receptor in the pig.

Neuropeptide S (NPS) precursor gene is present in most vertebrates. However, the genes of NPS and its receptor (NPSR), and their functions in the pig are currently not well understood. In order to clarify their physiological functions, it is essential to characterize in detail the distribution of NPS and NPSR. In this report, the cDNAs of NPS and NPSR were cloned and sequenced. Homology and phylogenetic analysis of NPS gene sequences were performed. The expression of NPS and NPSR mRNA in the pig was systemically investigated using semiquantitative reverse transcription polymerase chain reaction (RT-PCR), while the distribution of NPS was determined by immunohistochemistry. Our results demonstrated that the gene and predicted amino acid sequences of both NPS and NPSR were highly conserved. Phylogenetic analysis showed that NPS coding sequences from related species display high degrees of homology. NPS and NPSR mRNAs were widely expressed in various tissues of the pig. NPS mRNA was highly expressed in CNS, while NPSR mRNA was widely expressed in many tissues, with high expression in the hypophysis, endocrine tissues and glands. NPS protein also exhibited the different distribution in various organs. In the pig brain, NPS immunoreactive cells were mainly found in the diencephalon, pons and hypophysis, while immunoreactive fibres were widely distributed in the hypothalamus and olfactory bulb. In the peripheral organs, NPS immunoreactive cells were observed in the respiratory tract, alimentary tract, endocrine organs, genitourinary tract, lymphatic organs, muscle tissue, skin and skin appendages. By showing gene sequences and distribution of NPS and NPSR, these results suggest that NPS and NPSR in the pig might play important role in modulating a variety of physiological functions as in human and other animals. This research provided molecular and morphological data for further study of physiological function of NPS-NPSR system.

RINT-1 serves as a tumor suppressor and maintains Golgi dynamics and centrosome integrity for cell survival.

Faithful mitotic partitioning of the Golgi apparatus and the centrosome is critical for proper cell division. Although these two cytoplasmic organelles are probably coordinated during cell division, supporting evidence of this coordination is still largely lacking. Here, we show that the RAD50-interacting protein, RINT-1, is localized at the Golgi apparatus and the centrosome in addition to the endoplasmic reticulum. To examine the biological roles of RINT-1, we found that the homozygous deletion of Rint-1 caused early embryonic lethality at embryonic day 5 (E5) to E6 and the failure of blastocyst outgrowth ex vivo. About 81% of the Rint-1 heterozygotes succumbed to multiple tumor formation with haploinsufficiency during their average life span of 24 months. To pinpoint the cellular function of RINT-1, we found that RINT-1 depletion by RNA interference led to the loss of the pericentriolar positioning and dispersal of the Golgi apparatus and concurrent centrosome amplification during the interphase. Upon mitotic entry, RINT-1-deficient cells exhibited multiple abnormalities, including aberrant Golgi dynamics during early mitosis and defective reassembly at telophase, increased formation of multiple spindle poles, and frequent chromosome missegregation. Mitotic cells often underwent cell death in part due to the overwhelming cellular defects. Taken together, these findings suggest that RINT-1 serves as a novel tumor suppressor essential for maintaining the dynamic integrity of the Golgi apparatus and the centrosome, a prerequisite to their proper coordination during cell division.

Inactivation of CtIP leads to early embryonic lethality mediated by G1 restraint and to tumorigenesis by haploid insufficiency.

CtIP interacts with a group of tumor suppressor proteins including RB (retinoblastoma protein), BRCA1, Ikaros, and CtBP, which regulate cell cycle progression through transcriptional repression as well as chromatin remodeling. However, how CtIP exerts its biological function in cell cycle progression remains elusive. To address this issue, we generated an inactivated Ctip allele in mice by inserting a neo gene into exon 5. The corresponding Ctip(-/-) embryos died at embryonic day 4.0 (E4.0), and the blastocysts failed to enter S phase but accumulated in G(1), leading to a slightly elevated cell death. Mouse NIH 3T3 cells depleted of Ctip were arrested at G(1) with the concomitant increase in hypophosphorylated Rb and Cdk inhibitors, p21. However, depletion of Ctip failed to arrest Rb(-/-) mouse embryonic fibroblasts (MEF) or human osteosarcoma Saos-2 cells at G(1), suggesting that this arrest is RB dependent. Importantly, the life span of Ctip(+/-) heterozygotes was shortened by the development of multiple types of tumors, predominantly, large lymphomas. The wild-type Ctip allele and protein remained detectable in these tumors, suggesting that haploid insufficiency of Ctip leads to tumorigenesis. Taken together, this finding uncovers a novel G(1)/S regulation in that CtIP counteracts Rb-mediated G(1) restraint. Deregulation of this function leads to a defect in early embryogenesis and contributes, in part, to tumor formation.