Photosystem I complexes associated with fucoxanthin-chlorophyll-binding proteins from a marine centric diatom, Chaetoceros gracilis

Diatoms occupy a key position as a primary producer in the global aquatic ecosystem. We developed methods to isolate highly intact thylakoid membranes and the photosystem I (PS I) complex from a marine centric diatom, Chaetoceros gracilis. The PS I reaction center (RC) was purified as a super complex with light-harvesting fucoxanthin-chlorophyll (Chl)-binding proteins (FCP). The super complex contained 224 Chl a, 22 Chl c, and 55 fucoxanthin molecules per RC. The apparent molecular mass of the purified FCP-PS I super complex (approximately 1000 kDa) indicated that the super complex was composed of a monomer of the PS I RC complex and about 25 copies of FCP. The complex contained menaquinone-4 as the secondary electron acceptor A1 instead of phylloquinone. Time-resolved fluorescence emission spectra at 77 K indicated that fast (16 ps) energy transfer from a Chl a band at 685 nm on FCP to Chls on the PS I RC complex occurs. The ratio of fucoxanthin to Chl a on the PS I-bound FCP was lower than that of weakly bound FCP, suggesting that PS I-bound FCP specifically functions as the mediator of energy transfer between weakly bound FCPs and the PS I RC.     

Annexin A4 Is Involved in Proliferation,Chemo-Resistance and Migration and Invasion in Ovarian Clear Cell Adenocarcinoma Cells

Ovarian clear cell adenocarcinoma (CCC) is the second most common subtype of ovarian cancer after high-grade serous adenocarcinomas. CCC tends to develop resistance to the standard platinum-based chemotherapy, and has a poor prognosis when diagnosed in advanced stages. The ANXA4 gene, along with its product, a Ca⁺⁺-binding annexin A4 (ANXA4) protein, has been identified as the CCC signature gene. We reported two subtypes of ANXA4 with different isoelectric points (IEPs) that are upregulated in CCC cell lines. Although several in vitro investigations have shown ANXA4 to be involved in cancer cell proliferation, chemoresistance, and migration, these studies were generally based on its overexpression in cells other than CCC. To elucidate the function of the ANXA4 in CCC cells, we established CCC cell lines whose ANXA4 expressions are stably knocked down. Two parental cells were used: OVTOKO contains almost exclusively an acidic subtype of ANXA4, and OVISE contains predominantly a basic subtype but also a detectable acidic subtype. ANXA4 knockdown (KO) resulted in significant growth retardation and greater sensitivity to carboplatin in OVTOKO cells. ANXA4-KO caused significant loss of migration and invasion capability in OVISE cells, but this effect was not seen in OVTOKO cells. We failed to find the cause of the different IEPs of ANXA4, but confirmed that the two subtypes are found in clinical CCC samples in ratios that vary by patient. Further investigation to clarify the mechanism that produces the subtypes is needed to clarify the function of ANXA4 in CCC, and might allow stratification and improved treatment strategies for patients with CCC.     

Innate immune cells are dispensable for regenerative growth of imaginal discs

Following tissue damage the immune response, including inflammation, has been considered an inevitable condition to build the host defense against invading pathogens. The recruitment of innate immune leukocytes to injured tissue is observed in both vertebrates and invertebrates. However, it is still not conclusive whether the inflammatory response is also indispensable for the wound healing process by itself, in addition to its role in microbial clearance. In this study we determine the requirement of innate immune cells, both hemocytes and fat body cells, in Drosophila imaginal disc regeneration. We investigate wound healing and regenerative cell proliferation of damaged imaginal discs under immunodeficient conditions. To delay development of Drosophila at matured third instar larval stage we used a sterol-mutant erg2 knock-out yeast strain in the medium. This dietary-controlled developmental arrest allowed us to generate larvae free of immune cells without interfering with their larval development. In addition, this approach allowed uncoupling regenerative cell proliferation of damaged discs from their normal developmental growth. We furthermore examined the regenerative cell proliferation of fragmented imaginal discs by transplantation into host flies deficient of immune cells. We demonstrate that the damaged/fragmented discs in immune cells deficient conditions still exhibit regenerative cell proliferation comparable to those of control samples. These results suggest that recruitment of immune cells is not a prerequisite for the regenerative growth of damaged imaginal discs.     

Osteoprotegerin reduces the serum level of receptor activator of NF-kappaB ligand derived from osteoblasts

Osteoprotegerin (OPG) is a decoy receptor for receptor activator of NF-kappaB ligand (RANKL). We previously reported that OPG deficiency elevated the circulating level of RANKL in mice. Using OPG(-/-) mice, we investigated whether OPG is involved in the shedding of RANKL by cells expressing RANKL. Osteoblasts and activated T cells in culture released a large amount of RANKL in the absence of OPG. OPG or a soluble form of receptor activator of NF-kappaB (the receptor of RANKL) suppressed the release of RANKL from those cells. OPG- and T cell-double-deficient mice showed an elevated serum RANKL level equivalent to that of OPG(-/-) mice, indicating that circulating RANKL is mainly derived from bone. The serum level of RANKL in OPG(-/-) mice was increased by ovariectomy or administration of 1alpha,25-dihydroxyvitamin D(3). Expression of RANKL mRNA in bone, but not thymus or spleen, was increased in wild-type and OPG(-/-) mice by 1alpha,25-dihydroxyvitamin D(3). These results suggest that OPG suppresses the shedding of RANKL from osteoblasts and that the serum RANKL in OPG(-/-) mice exactly reflects the state of bone resorption.     

Development of a multi-step leukemogenesis model of MLL-rearranged leukemia using humanized mice

Mixed-lineage-leukemia (MLL) fusion oncogenes are intimately involved in acute leukemia and secondary therapy-related acute leukemia. To understand MLL-rearranged leukemia, several murine models for this disease have been established. However, the mouse leukemia derived from mouse hematopoietic stem cells (HSCs) may not be fully comparable with human leukemia. Here we developed a humanized mouse model for human leukemia by transplanting human cord blood-derived HSCs transduced with an MLL-AF10 oncogene into a supra-immunodeficient mouse strain, NOD/Shi-scid, IL-2Rγ(-/-) (NOG) mice. Injection of the MLL-AF10-transduced HSCs into the liver of NOG mice enhanced multilineage hematopoiesis, but did not induce leukemia. Because active mutations in ras genes are often found in MLL-related leukemia, we next transduced the gene for a constitutively active form of K-ras along with the MLL-AF10 oncogene. Eight weeks after transplantation, all the recipient mice had developed acute monoblastic leukemia (the M5 phenotype in French-American-British classification). We thus successfully established a human MLL-rearranged leukemia that was derived in vivo from human HSCs. In addition, since the enforced expression of the mutant K-ras alone was insufficient to induce leukemia, the present model may also be a useful experimental platform for the multi-step leukemogenesis model of human leukemia.     

Wobble modification deficiency in mutant tRNAs in patients with mitochondrial diseases

Point mutations in mitochondrial (mt) tRNA genes are associated with a variety of human mitochondrial diseases. We have shown previously that mt tRNA(Leu(UUR)) with a MELAS A3243G mutation and mt tRNA(Lys) with a MERRF A8344G mutation derived from HeLa background cybrid cells are deficient in normal taurine-containing modifications [taum(5)(s(2))U; 5-taurinomethyl-(2-thio)uridine] at the anticodon wobble position in both cases. The wobble modification deficiency results in defective translation. We report here wobble modification deficiencies of mutant mt tRNAs from cybrid cells with different nuclear backgrounds, as well as from patient tissues. These findings demonstrate the generality of the wobble modification deficiency in mutant tRNAs in MELAS and MERRF.     

Relationship between Item Responses of Negative Affect Items and the Distribution of the Sum of the Item Scores in the General Population

BackgroundSeveral studies have shown that total depressive symptom scores in the general population approximate an exponential pattern, except for the lower end of the distribution. The Center for Epidemiologic Studies Depression Scale (CES-D) consists of 20 items, each of which may take on four scores: “rarely,” “some,” “occasionally,” and “most of the time.” Recently, we reported that the item responses for 16 negative affect items commonly exhibit exponential patterns, except for the level of “rarely,” leading us to hypothesize that the item responses at the level of “rarely” may be related to the non-exponential pattern typical of the lower end of the distribution. To verify this hypothesis, we investigated how the item responses contribute to the distribution of the sum of the item scores.MethodsData collected from 21,040 subjects who had completed the CES-D questionnaire as part of a Japanese national survey were analyzed. To assess the item responses of negative affect items, we used a parameter r, which denotes the ratio of “rarely” to “some” in each item response. The distributions of the sum of negative affect items in various combinations were analyzed using log-normal scales and curve fitting.ResultsThe sum of the item scores approximated an exponential pattern regardless of the combination of items, whereas, at the lower end of the distributions, there was a clear divergence between the actual data and the predicted exponential pattern. At the lower end of the distributions, the sum of the item scores with high values of r exhibited higher scores compared to those predicted from the exponential pattern, whereas the sum of the item scores with low values of r exhibited lower scores compared to those predicted.ConclusionsThe distributional pattern of the sum of the item scores could be predicted from the item responses of such items.     

The clinicopathological significance of angiogenesis in hindgut neuroendocrine tumors obtained via an endoscopic procedure

Background

As the World Health Organization grading system for gastroenteropancreatic-neuroendocrine tumors (GEP-NETs) may not always correlate with tumor progression, it is imperative that other independent predictors of tumor progression be established. To identify such predictors, we conducted a retrospective histopathological study of hindgut NETs, obtained from endoscopic procedures, and used statistical analyses to evaluate predictive factors.

Methods

We first obtained clinicopathological data of cases of hindgut NETs. Tissue sections from tumor samples were prepared and subjected to pathological examination. In particular, we calculated the microvessel density (MVD) and lymphatic microvessel density (LMVD) values, and performed appropriate statistical analyses.

Results

A total of 42 cases of hindgut NETs were selected for the study, 41 from the rectum and 1 from the sigmoid colon. Based on the Ki-67 labeling index, 34 cases were classified as NET G1 tumors and 8 as NET G2 tumors. MVD values ranged from 1.4/mm² to 73.9/mm² and LMVD values from 0/mm² to 22.9/mm². MVD and LMVD were identified as risk factors for venous and lymphatic invasion of hindgut NETs. Moreover, MVD positively correlated with the maximum diameter of the tumor.

Conclusions

Tumor progression of NETs may cause angiogenesis and lymphangiogenesis, via an unknown mechanism, as well as lymphovascular invasion. Angiogenesis likely plays an important role in occurrence and progression in the initial phase of hindgut NETs.

     

Angiographic Lesion Complexity Score and In-Hospital Outcomes after Percutaneous Coronary Intervention

Objective

We devised a percutaneous coronary intervention (PCI) scoring system based on angiographic lesion complexity and assessed its association with in-hospital complications.

Background

Although PCI is finding increasing application in patients with coronary artery disease, lesion complexity can lead to in-hospital complications.

Methods

Data from 3692 PCI patients were scored based on lesion complexity, defined by bifurcation, chronic total occlusion, type C, and left main lesion, along with acute thrombus in the presence of ST-segment elevation myocardial infarction (1 point assigned for each variable).

Results

The patients’ mean age was 67.5 +/- 10.8 years; 79.8% were male. About half of the patients (50.3%) presented with an acute coronary syndrome, and 2218 (60.1%) underwent PCI for at least one complex lesion. The patients in the higher-risk score groups were older (p < 0.001) and had present or previous heart failure (p = 0.02 and p = 0.01, respectively). Higher-risk score groups had significantly higher in-hospital event rates for death, heart failure, and cardiogenic shock (from 0 to 4 risk score; 1.7%, 4.5%, 6.3%, 7.1%, 40%, p < 0.001); bleeding with a hemoglobin decrease of >3.0 g/dL (3.1%, 11.0%, 13.1%, 10.3%, 28.6%, p < 0.001); and postoperative myocardial infarction (1.5%, 3.1%, 3.8%, 3.8%, 10%, p = 0.004), respectively. The association with adverse outcomes persisted after adjustment for known clinical predictors (odds ratio 1.72, p < 0.001).

Conclusion

The complexity score was cumulatively associated with in-hospital mortality and complication rate and could be used for event prediction in PCI patients.     

Plasma free amino acid profiling of five types of cancer patients and its application for early detection

Background

Recently, rapid advances have been made in metabolomics-based, easy-to-use early cancer detection methods using blood samples. Among metabolites, profiling of plasma free amino acids (PFAAs) is a promising approach because PFAAs link all organ systems and have important roles in metabolism. Furthermore, PFAA profiles are known to be influenced by specific diseases, including cancers. Therefore, the purpose of the present study was to determine the characteristics of the PFAA profiles in cancer patients and the possibility of using this information for early detection.

Methods and Findings

Plasma samples were collected from approximately 200 patients from multiple institutes, each diagnosed with one of the following five types of cancer: lung, gastric, colorectal, breast, or prostate cancer. Patients were compared to gender- and age- matched controls also used in this study. The PFAA levels were measured using high-performance liquid chromatography (HPLC)–electrospray ionization (ESI)–mass spectrometry (MS). Univariate analysis revealed significant differences in the PFAA profiles between the controls and the patients with any of the five types of cancer listed above, even those with asymptomatic early-stage disease. Furthermore, multivariate analysis clearly discriminated the cancer patients from the controls in terms of the area under the receiver-operator characteristics curve (AUC of ROC >0.75 for each cancer), regardless of cancer stage. Because this study was designed as case-control study, further investigations, including model construction and validation using cohorts with larger sample sizes, are necessary to determine the usefulness of PFAA profiling.

Conclusions

These findings suggest that PFAA profiling has great potential for improving cancer screening and diagnosis and understanding disease pathogenesis. PFAA profiles can also be used to determine various disease diagnoses from a single blood sample, which involves a relatively simple plasma assay and imposes a lower physical burden on subjects when compared to existing screening methods.