Niche Tet maintains germline stem cells independently of dioxygenase activity

Ten-eleven translocation (TET) proteins are dioxygenases that convert 5-methylcytosine (5mC) into 5-hydroxylmethylcytosine (5hmC) in DNA and RNA. However, their involvement in adult stem cell regulation remains unclear. Here, we identify a novel enzymatic activity-independent function of Tet in the Drosophila germline stem cell (GSC) niche. Tet activates the expression of Dpp, the fly homologue of BMP, in the ovary stem cell niche, thereby controlling GSC self-renewal. Depletion of Tet disrupts Dpp production, leading to premature GSC loss. Strikingly, both wild-type and enzyme-dead mutant Tet proteins rescue defective BMP signaling and GSC loss when expressed in the niche. Mechanistically, Tet interacts directly with Bap55 and Stat92E, facilitating recruitment of the Polybromo Brahma associated protein (PBAP) complex to the dpp enhancer and activating Dpp expression. Furthermore, human TET3 can effectively substitute for Drosophila Tet in the niche to support BMP signaling and GSC self-renewal. Our findings highlight a conserved novel catalytic activity-independent role of Tet as a scaffold protein in supporting niche signaling for adult stem cell self-renewal.

Gap junction-transported cAMP from the niche controls stem cell progeny differentiation

The niche has been shown to control stem cell self-renewal in different tissue types and organisms. Recently, a separate niche has been proposed to control stem cell progeny differentiation, called the differentiation niche. However, it remains poorly understood whether and how the differentiation niche directly signals to stem cell progeny to control their differentiation. In the Drosophila ovary, inner germarial sheath (IGS) cells contribute to two separate niche compartments for controlling both germline stem cell (GSC) self-renewal and progeny differentiation. In this study, we show that IGS cells express Inx2 protein, which forms gap junctions (GJs) with germline-specific Zpg protein to control stepwise GSC lineage development, including GSC self-renewal, germline cyst formation, meiotic double-strand DNA break formation, and oocyte specification. Germline-specific Zpg and IGS-specific Inx2 knockdowns cause similar defects in stepwise GSC development. Additionally, secondary messenger cAMP is transported from IGS cells to GSCs and their progeny via GJs to activate PKA signaling for controlling stepwise GSC development. Therefore, this study demonstrates that the niche directly controls GSC progeny differentiation via the GJ-cAMP-PKA signaling axis, which provides important insights into niche control of stem cell differentiation and highlights the importance of GJ-transported cAMP in tissue regeneration. This may represent a general strategy for the niche to control adult stem cell development in various tissue types and organisms since GJs and cAMP are widely distributed.

Body mass index increases the recurrence risk of breast cancer: a dose-response meta-analysis from 21 prospective cohort studies

OBJECTIVE

The purpose of this study was to investigate the effect of body mass index (BMI) on the recurrence risk of breast cancer.

STUDY DESIGN

Dose-response meta-analysis.

METHODS

Cohort studies that included BMI and the recurrence of breast cancer were selected through various databases including PubMed, Web of Science, the China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals (VIP), and Wanfang Data Knowledge Service Platform (WanFang) until November 30, 2021. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of literature. A two-stage random-effects meta-analysis was performed to assess the dose-response relationship between BMI and breast cancer recurrence risk. Heterogeneity between studies is assessed using I².

RESULTS

The relative risk (RR) of BMI <25 kg/m² vs BMI ≥25 kg/m², BMI <30 kg/m² vs BMI ≥30 kg/m² were 1.09 (95% CI: 1.00-1.19) and 1.15 (95% CI: 1.04-1.27), suggesting that BMI had a significant effect on the recurrence risk of breast cancer, and there might be a dose-response relationship between them. A total of 21 studies were included in dose-response meta-analysis, which showed that there was a positive linear correlation between BMI and the risk of recurrence (RR = 1.02, 95% CI: 1.01-1.03). For every 1 kg/m² increment of BMI, the risk of recurrence increased by approximately 2%. In subgroup analyses, positive linear dose-response relationships between BMI and recurrence risk were observed among Asian and study period >10 years groups. For every 1 kg/m² increment of BMI, the risk of recurrence increased by 3.41% and 1.87%, respectively.

CONCLUSIONS

The recurrence risk of breast cancer increases with BMI, which is most obvious among Asian women.

P-380 Single-cell transcriptome analysis reveales that expression changes of the endometrium in repeated implantation failure are altered by HPV-mediated CXCL chemokine secretion

Study question

What are the mechanisms and molecular expression patterns of reduced endometrial receptivity in repeated implantation failure (RIF) after human papillomavirus (HPV) infection?

Summary answer

The single-cell transcriptomic analysis identifies the expression changes of endometrium in RIF via HPV-mediated CXCL chemokines secretion in single-cell resolution.

What is known already

Regardless of the advance of in vitro fertilization (IVF), RIF is still a formidable challenge for couples and physicians in clinical treatment. In infertile couples, a reduction in natural and assisted cumulative pregnancy rate and an increase in miscarriage rate are related to the HPV infection.

Study design, size, duration

Cross-sectional clinical studies with 322 infertile couples undergoing IVF were integrated to demonstrate the associations between HPV infection and reproductive outcomes (pregnancy rate and miscarriage). Descriptive analysis of single-cell transcriptome data of uteruses, and transcriptome profiles of mid-secretory endometrium from 16 healthy fertile women and 38 repeated IVF failure women were analyzed to identify the expression patterns of endometrium in RIF. In vitro assays were used to validate the expression patterns in endometrium.

Participants/materials, setting, methods

322 infertile couples, single-cell transcriptome data of uteruses (human and mouse), and transcriptome profiles of endometrium (16 normal vs. 38 RIF) were used to analyze the association between HPV infection and reduced endometrial receptivity. HPV genes (E1, E2, E4, and E5) were transfected into a human normal endometrial epithelial cell line (hEM3), and immunohistochemistry, Westerns, quantitative PCR were used to validate the changes of CXCL chemokines in the endometrium in vitro.

Main results and the role of chance

Integrated cross-sectional studies demonstrate that HPV+ women exhibit a decreased pregnancy rate (83.09%) as compared with HPV- women (55.17%, P &lt;0.001), and a higher miscarriage rate (62.5% vs. 16.7%, P &lt;0.001) and the relative risk of spontaneous abortion (odd ratio=2.84, P &lt;0.0001) were observed in HPV+ women. Transcriptome profiling analysis identified the enrichment of the processes related to viral protein interaction with cytokine and cytokine receptor and cytokine-cytokine receptor interaction, especially in the CXCL chemokine family. Further analysis of single-cell transcriptome demonstrated that the changed expression patterns were associated with endometrial epithelial cells and immune cells, including macrophage dendritic cells, monocytes, and granulocytes. Moreover, in vitro assays validated the HPV-mediated CXCL chemokines secretion, which played the role in recruiting immune cells.

Limitations, reasons for caution

The current findings are based on the single-cell profiling analysis in normal endometrium. In addition, the in vivo response of the HPV infection may differ from the in vitro assay, which should be validated in the HPV infection couples.

Wider implications of the findings

Our study demonstrated the expression changes of endometrium in RIF via HPV-mediated CXCL chemokines secretion, which provided insight into the mechanisms of HPV-induced reduced endometrial receptivity in single-cell resolution.

Trial registration number

not applicable

Spatiotemporal changes of CT manifestations in 110 patients with COVID-19 pneumonia

OBJECTIVE

The aim of the study was to analyze spatiotemporal changes of CT manifestations in patients with COVID-19 pneumonia.

PATIENTS AND METHODS

In this retrospective review, 110 patients with confirmed COVID-19 by RT-PCR form February 16, 2020, to March 28, 2020 were included. A total of 449 CT scans were reviewed. We analyze the type and distribution of lung abnormalities, and CT general assessment and lesion area statistics were performed. Patients were divided into mild, moderate, and severe disease based on Chinese guidelines: mild (patients with minimal symptoms, CT scans showed no pneumonia or a small area of pneumonia infection), moderate (different extent of clinical manifestations and CT scans showed multiple pneumonia infections in both lungs), severe disease (respiratory distress, CT scans lesion area exceeds 50%, and the lesion contains consolidation). The proportion of patients with mild, moderate and severe diseases was counted.

RESULTS

The CT score and the area involved reached a peak (median 10) on illness days 7-12, and then, continued to be at a high level. The main abnormal pattern after symptoms appeared GGO (36/94 [36%] to 40/65 [62%] in different periods). The proportion of mixed reached its peak on illness days 13-18 (36/93 [39%]). Pure GGO was the most common subtype of GGO (24 of 60 CT scans [40%] to 23 of 33 CT scans [70%]) after symptoms onset. The ratio of GGO with irregular lines and interfaces peaked on illness days 7-12 (6/34 [18%]). The lesions are mainly distributed on both sides and under the pleura. 76/84 (90%) of discharged patients had residual lesions on the final CT scans. 4 confirmed patients' CT scans did not show lesions (on illness days 1-24 days). There were 47 mild cases (42.7%), 46 moderate cases (41.8%), and 7 severe cases (6.3%).

CONCLUSIONS

The degree of lung abnormality on the CT of the patients reached the peak on the 7th to 12th days of the disease. CT performance changes with time have a certain regularity, which may indicate the progress and recovery of the disease. 90% of patients still observed residual lung abnormalities in CT images at the time of discharge. There were 4 confirmed cases where the CT images did not show the lesion; hence, CT cannot be used as a basis for judging COVID-19 as a single tool.

Body mass index cut-off points for predicting chronic non-communicable disease should differ by gender and age group

OBJECTIVES

The objective of this study to determine whether body mass index (BMI) in different genders and age groups need different thresholds when predicting chronic non-communicable diseases (CNCDs).

STUDY DESIGN

This is a cross-sectional study.

METHODS

Data were obtained from the China Health and Nutrition Survey conducted in 2009. Sequential sample cluster analysis was used to group age according to BMI. Propensity score matching was used to eliminate the influence of age. Receiver operating characteristic curve based on gender and age group was used to evaluate the cut-off values and efficiency of BMI in each group.

RESULTS

A total of 8469 individuals were enrolled in this study. Results of sequential sample cluster analyses showed age was divided into three groups: 18-39, 40-59 and 60-99 years. There were significant differences in the distribution of BMI among the three groups for both males and females (P < 0.001). Statistical differences were observed in the distribution of BMI between genders in the 18-39- and 60-99-year-old age groups (P < 0.001). For men, the cut-off values of BMI were ≥25 kg/m², ≥24 kg/m² and ≥23 kg/m² in the 18-39, 40-59 and 60-99 years old groups, respectively; for women, the corresponding cut-off points were ≥25 kg/m², ≥23 kg/m² and ≥25 kg/m² in groups.

CONCLUSIONS

The thresholds for BMI might be different between gender and age group. In addition, it might not be suitable to determine cut-off values of BMI to predict CNCDs for people aged ≥60 years.

Trends of Activities of Daily Living Disability Situation and Association with Chronic Conditions among Elderly Aged 80 Years and Over in China

OBJECTIVES

In China, few studies reported the disability situation and the association between disabilities with chronic conditions in aged people. This study investigates the cross-sectional trends of prevalence and severity of activities of daily living disability (ADL) in Chinese oldest-old people from 1998 to 2008, and identified the potential risk factors of disability.

DESIGN

A combination of population-based longitudinal prospective study and probabilistically sampling cross-sectional studies.

SETTING

The Chinese Longitudinal Healthy Longevity Survey (CLHLS) was based on a random sampling of aged people from twenty-two provinces in China.

PARTICIPANTS

A total of 52,667 participants aged from 80 years old to 105 years old sampled in the year of 1998 (n=8,768), 2000 (n=10,940), 2002 (n=10,905), 2005 (n=10,396) and 2008 (n=11,658) were analyzed respectively.

RESULTS

The prevalence of ADL disability decreased from the year of 1998 (18%) to 2008 (12%). The disability prevalence significantly increased in 2002 and decreased in 2008 (P<0.001) in total participants than the year of 1998. The prevalence trends of low ADL disability level were almost identical with that of the total ADL disability. Stroke/cerebrovascular disease (CVD) and cognitive impairment were the strongest risk factors of disability. Vision impairment became less associated with ADL disability (P=0.045), while the association between multimorbidity and ADL disability became stronger (P=0.033).

CONCLUSIONS

The prevalence of ADL disability declined among the oldest-old population in China from the year of 1998 to 2008 without obeying a linear pattern. Temporal trends of ADL disability mainly attributed to the change of low disability level prevalence. Stroke/CVD and cognitive impairment were the most common risk factors of disability. Vision impairment caused disability has become less common, while risks of multimorbidity related disability increased.

Anti-hepatoma activity of the stiff branched β-d-glucan and effects of molecular weight

The water soluble β-d-glucan AF1 with short branches isolated from Auricularia auricula-judae exhibited significant anti-hepatoma activities, and it was confirmed that AF1 had stiff chains and could induce cancer cell apoptosis and anti-angiogenesis through activating immune responses.

Synthesis of 6-O-poly(ϵ-caprolactone)-L-ascorbic acid and its controlled release from supramolecular polymer micelles

Lipophilic 6-O-poly (ϵ-caprolactone)-L-ascorbic acid (AA-6-PCL) is synthesized through ROP of ϵ-caprolactone (CL). The number of repeating CL units in the polymer chain varies from 6 to 19. AA-6-PCL loaded supramolecular polymer micelles (SMPMs) are constructed with β-cyclodextrin (β-CD) and PCL as blocks. Transmission electron microscopy images show a nanospheric morphology of the micelles with a size range of 43.3 ± 5.0 nm. The drug loading contents are 22.53-39.23% for AA-6-PCL. AA-6-PCL exhibits high radical scavenging capacity (93.96-96.73%) and efficient scavenging potency, and a cytotoxicity study proves the excellent cytocompatibility of AA-6-PCL loaded β-CD/PCL SMPMs, which altogether herald their potential application in the study of the induced pluripotent stem cells.

The improvement of amorpha-4,11-diene production by a yeast-conform variant

AIMS

To investigate the effect of the yeast-conform variant of the Artemisia annua gene encoding for amorpha-4,11-diene synthase (ADS) on the production of amorpha-4,11-diene in a transformed yeast.

METHODS AND RESULTS

The ADS gene was mutated to the yeast-conform variant ADSm. The ADSm synthesis was performed based on step-by-step extension of a short region of the gene through a series of polymerase chain reactions (PCR). The artificial ADSm gene contained codons preferred by the yeast translation machinery. The sequence was then integrated into a yeast expression vector pYeDP60. The fusion construct was active and the transformed yeast cells produced higher level of amorpha-4,11-diene compared with the plant gene-transformed yeast cells.

CONCLUSIONS

Strains transformed with the yeast-conform allele (ADSm) were more efficient in terms of production of amorpha-4,11-diene than those transformed with the plant gene.

SIGNIFICANCE AND IMPACT OF THE STUDY

We demonstrated that yeast-conform allele of foreign genes by serial PCR reactions can be a solution to low efficiency of heterologous gene expression in Saccharomyces cerevisiae cells.

The ratios of individual chemicals in a mixture determine the degree of joint effect: the climax hypothesis

A new hypothesis, the Climax Hypothesis, is proposed to describe how the ratios of individual chemicals influence the joint effects of chemical mixtures. This hypothesis is derived from a generalized approach using "isobolograms". With this hypothesis, one can predict that for a given mixture, a curvilinear correlation exists between the joint effects and the ratios of individual chemicals and that this curve has a climax at the equitoxic ratio. This prediction is supported by the observed toxicity to Vibrio fischeri of 18 mixtures (12 binary mixtures, 4 ternary mixtures, and 2 quaternary mixtures). With this prediction, the Climax Hypothesis has some promising applications such as controlling the discharge of effluents in environmental science, maximizing detoxifying effects in medicine, and optimizing combined pesticides in agriculture.

Human herpesvirus 6 open reading frame U12 encodes a functional beta-chemokine receptor

Human herpesvirus 6 (HHV- 6), which belongs to the betaherpesvirus subfamily and infects mainly T cells in vitro, causes acute and latent infections. HHV- 6 contains two genes (U12 and U51) that encode putative homologs of cellular G-protein-coupled receptors (GCR), while three other betaherpesviruses, human cytomegalovirus, murine cytomegalovirus, and human herpesvirus 7, have three, one, and two GCR-homologous genes, respectively. The U12 gene is expressed late in infection from a spliced mRNA. The U12 gene was cloned, and the protein was expressed in cells and analyzed for its biological characteristics. U12 functionally encoded a calcium-mobilizing receptor for beta-chemokines such as regulated upon activation, normal T expressed and secreted (RANTES), macrophage inflammatory proteins 1alpha and 1beta (MIP-1alpha and MIP-1beta) and monocyte chemoattractant protein 1 but not for the alpha-chemokine interleukin-8, suggesting that the chemokine selectivity of the U12 product was distinct from that of the known mammalian chemokine receptors. These findings suggested that the product of U12 may play an important role in the pathogenesis of HHV- 6 through transmembrane signaling by binding with beta-chemokines.

[Assessment of the toxicity of TAH on the cell lines of SO-Rb50 and SO-Rb70]

PURPOSE

MTT assay was evaluated on cytoxicity for suspension growing cell lines of SO-Rb50 and SO-Rb70, and the toxicity of TAH (the total alkaloid of peqanum harmala L) on the above cell lines was assessed.

METHODS

The relationships between cell number and optical density, between optical density and exposure time of MTT, and the stability of formazan crystal solution in MDSO were determined. And the toxicity of TAH on the cell lines of SO-Rb50 and SO-Rb70 in vitro with MTT assay was assessed.

RESULTS

There was a direct proportional relationship between the amount of cell number and its optical density; The optical density increased gradully within 12 hours of the MTT incubation time; The stable time of the formazan crystal solved in DMSO was 11 hours. The IC50 values (micrograms/ml) of TAH on SO-Rb50 were 10.66, 4.82 respectively for 48 and 72 hours; and on SO-Rb70 were 6.38, 4.2 respectively for 48 and 72 hours.

CONCLUSION

MTT assay can be used for suspension growing cell lines of SO-Rb50 and SO-Rb70: TAH has obvious toxicity to these two cell lines.

Correlation study on infrared thermography and nerve root signs in lumbar intervertebral disk herniation patient: a short report

OBJECTIVE

To determine whether infrared skin thermography is an objective measurement reflecting the seriousness of nerve root irritation in lumbar disk herniation patients.

DESIGN

Quantified nerve root signs by physical examination were collected from the patients along with the infrared skin temperature measurement on the lumbosacral region and posterior part of thighs. A correlation study was applied to observe the relation between the nerve root signs and the skin temperature before a successful conservative treatment (mainly spine manipulation), and between the alteration of nerve root signs and that of skin temperature after the treatment.

SETTING

Hospitalized care.

PATIENTS

Twenty-seven hospitalized samples with computed tomography or magnetic resonance approval were consecutively selected during the latter half of 1990.

MAIN OUTCOME MEASURE

Changes in nerve root signs.

RESULTS

The temperature difference between a troubled thigh and healthy one is significantly correlated to the score of the nerve root signs before the treatment; and the reduction of temperature difference between two thighs is also significantly correlated with decreasing score of nerve root signs after the treatment. The correlation between the temperature difference on the left and right sides of the lumbosacral region and the nerve root signs before the treatment is insignificant; and the variation of the temperature difference of the same region after the treatment is not correlated with the decreasing score of the nerve root signs.

CONCLUSION

Infrared skin thermography of lower extremities might be an objective sign in signaling the soothing process of the nerve root irritation in lumbar disk herniation patients, which may help a doctor in checking the responses of the patient to treatment.

Voltage-dependent Ca2+ channels in the plasma membrane and the vacuolar membrane of Arabidopsis thaliana

Voltage-dependent Ca2+ channels in the plasma membrane and the vacuolar membrane of Arabidopsis thaliana have been studied at the single-channel level using the patch-clamp technique. The Ca2+ channel in the plasma membrane opened for extracellular Ca2+ influx. The Ca2+ channel in the vacuolar membrane opened for cytoplasmic Ca2+ influx.

High-level expression and secretion of a lysine-containing analog of Escherichia coli heat-stable enterotoxin

The mechanism of action of the heat-stable enterotoxin STa secreted from enterotoxigenic forms of Escherichia coli has remained elusive, in part due to a tedious, low-yield purification procedure. We report here a method for obtaining large amounts of a biologically active lysine-containing analog of STa. Initial attempts to express the toxin using an expression vector that did not encode a signal sequence resulted in no biologically active material being recovered either from lysed cells or as a secretory product. However, use of the secretion vector pJAL36, which contains the STII enterotoxin signal sequence, allowed large amounts of an STa derivative containing the additional sequence Ser-Thr-Lys at the amino terminus of the mature enterotoxin to be readily purified from culture supernatants. This enterotoxin analog, known as KSTa-1, was equal in biological and receptor binding activity to the native toxin STa. The lysine residue present in KSTa-1 promises to be useful as a reactive amino acid that is readily derivatized to allow coupling of the enterotoxin to supports for affinity chromatography and antigenic conjugates. Additionally, the insertion of the lysine residue carboxy terminal to the Ser-Thr sequence adds a reversible "handle" to the toxin sequence in that the Ser-Thr-Lys segment can be removed by treatment with trypsin, releasing the native form of STa.