Clinical Study on Systemic Lupus Erythematosus Complicated with Knee Bone Infarction.

Objective: The present study aims to (1) analyze the clinical characteristics and related influencing factors of knee bone infarction in systemic lupus erythematosus (SLE) and (2) improve the understanding of SLE complicated with knee bone infarction. Methods: The data of patients with SLE complicated with knee bone infarction were retrospectively analysed; patients with SLE during the same period who matched in age, gender, and disease duration were selected as control subjects, with a 1 : 1 ratio with the SLE group. The clinical data were collected to analyze the risk factors for SLE complicated with knee bone infarction. Results: In a total of 36 (6.4%) of 563 patients aged 19-33 (25.8 ± 4.8) years who had SLE during the same period, the disease was complicated with knee bone infarction. The diagnosis of knee bone infarction was made at an SLE duration of 7-65 (26.2 ± 15.7) months. During the SLE course, knee bone infarction occurred within 1 year in 6 cases (16.7%), within 1-5 years in 28 cases (77.8%), and in >5 years in 2 cases (5.6%). Raynaud's phenomenon incidence and anti-nRNP antibody positivity were significantly higher in the knee bone infarction group than in the control group (P < 0.01 and P < 0.05, respectively). The cumulative glucocorticoid dose at 1, 3, and 6 months was significantly higher in the knee bone infarction group than in the control group (P < 0.05). SLE complicated with knee necrosis had a statistically significant rank correlation with Raynaud's phenomenon (r = 0.445, P < 0.001), anti-nRNP antibody (r = 0.309, P=0.008), and renal injury (r = 0.252, P=0.032). The multivariate analysis of SLE complicated with knee bone infarction showed that Raynaud's phenomenon was an independent influencing factor for the complicated knee bone infarction in SLE patients (OR = 4.938, P=0.004), and the probability of SLE complicated with knee bone infarction in Raynaud's phenomenon positive patients was 4.938 times that of Raynaud's phenomenon negative patients. Conclusions: The risk of knee bone infarction was relatively high in patients with SLE within a 5-year disease course and in young patients. The risk factors were Raynaud's phenomenon, anti-nRNP antibody positivity, and early high-dose glucocorticoid therapy.

[NKX2.5 and TBX5 gene mutations in in vitro fertilization children with congenital heart disease].

OBJECTIVE: To explore the differences of NKX2.5 and TBX5 gene mutations between in vitro fertilization (IVF) children with congenital heart disease (CHD) and naturally conceived children with CHD. METHODS: Blood samples from 68 IVF children with CHD and 98 naturally conceived children with CHD were collected. The mutations in coding regions 1 and 2 of the NKX2.5 gene, and coding regions 4, 5, and 8 of the TBX5 gene were examined by polymerase chain reaction (PCR) and DNA sequencing. RESULTS: An A-to-G mutation at nucleotide 63 (c.63A>G) in coding region 1 of the NKX2.5 gene was found in both IVF and naturally conceived children with CHD. There were no significant differences in genotype and allele frequencies at c.63A>G locus of the NKX2.5 gene between the two groups. No mutations were detected in coding region 2 of the NKX2.5 gene and coding regions 4, 5 and 8 of the TBX5 gene. CONCLUSIONS: There is no difference in NKX2.5 and TBX5 gene mutations between IVF and naturally conceived children with CHD. Therefore, it is presumed that assisted reproductive technology may not lead to mutations in the NKX2.5 and TBX5 genes.

[Neonatal complications and birth defects in infants conceived by in vitro fertilization].

OBJECTIVE: To investigate the survival quality of infants conceived by in vitro fertilization (IVF) and to identify the factors that cause birth defects and neonatal complications in IVF infants. METHODS: The study included 150 IVF infants (IVF group) and 200 naturally conceived infants (control group). Indicators such as birth situation, gestational disease, birth defects, and neonatal complications were compared between groups. The influencing factors for birth defects and neonatal complications were analyzed by non-conditional logistic regression analysis. RESULTS: Compared with the control group, the IVF group had increased incidences of twin pregnancy and low birth weight (P<0.01) but decreased average birth weight (P<0.05). In the IVF group, the mother's age was elder, with higher incidence of cesarean section, premature rupture of membranes, and pregnancy complications, as compared with the control group (P<0.05). There was no significant difference in the incidence of birth defects between the two groups (P>0.05). The IVF group had higher incidence rates of low birth weight and neonatal scleroderma (P<0.05), with a longer hospital stay (P<0.01), as compared with the control group. The non-conditional logistic regression analysis indicated that IVF, prematurity, twin pregnancy, and pregnancy complications were risk factors for low birth weight (P<0.05). CONCLUSIONS: There is no significant difference in the incidence of birth defects between IVF and naturally conceived infants. However, IVF infants have higher incidences of twin pregnancy and low birth weight, with a longer hospital stay, as compared with naturally conceived infants. Natural conceiving, avoiding prematurity, twin pregnancy, and pregnancy complications will reduce the incidence of low birth weight.

UGT74D1 is a novel auxin glycosyltransferase from Arabidopsis thaliana.

Auxin is one type of phytohormones that plays important roles in nearly all aspects of plant growth and developmental processes. The glycosylation of auxins is considered to be an essential mechanism to control the level of active auxins. Thus, the identification of auxin glycosyltransferases is of great significance for further understanding the auxin regulation. In this study, we biochemically screened the group L of Arabidopsis thaliana glycosyltransferase superfamily for enzymatic activity toward auxins. UGT74D1 was identified to be a novel auxin glycosyltransferase. Through HPLC and LC-MS analysis of reaction products in vitro by testing eight substrates including auxins and other compounds, we found that UGT74D1 had a strong glucosylating activity toward indole-3-butyric acid [IBA], indole-3-propionic acid [IPA], indole-3-acetic acid [IAA] and naphthaleneacetic acid [NAA], catalyzing them to form corresponding glucose esters. Biochemical characterization showed that this enzyme had a maximum activity in HEPES buffer at pH 6.0 and 37°C. In addition, the enzymatic activity analysis of crude protein and the IBA metabolite analysis from transgenic Arabidopsis plants overexpressing UGT74D1 gene were also carried out. Experimental results indicated that over-production of the UGT74D1 in plants indeed led to increased level of the glucose conjugate of IBA. Moreover, UGT74D1 overexpression lines displayed curling leaf phenotype, suggesting a physiological role of UGT74D1 in affecting the activity of auxins. Our current data provide a new target gene for further genetic studies to understand the auxin regulation by glycosylation in plants.

Glucosyltransferase UGT76C1 finely modulates cytokinin responses via cytokinin N-glucosylation in Arabidopsis thaliana.

Cytokinins are master regulators of plant growth and development. The glucosyltransferase UGT76C1 capable of N-glucosylation of different cytokinins at the N(7)- and N(9)-position was previously identified in Arabidopsis thaliana, but its physiological relevance in plants remains unclear. In the present work, we investigated the physiological characteristics of UGT76C1 mutant (ugt76c1) and its overexpressors. Under normal growth conditions, although ugt76c1 plants and UGT76C1 overexpressors did not display obvious phenotypic alteration, ugt76c1 plants significantly reduced the accumulation of cytokinin N-glucosides, whereas UGT76C1 overexpressors increased cytokinin N-glucosides. Unexpectedly, the concentrations of free forms of cytokinins (mainly trans-zeatin and N(6)-isopentenyladenine) were comparable to those of the wild type. Upon application of exogenous cytokinin, the mutant showed the same tendency of more sensitive cytokinin response in primary root elongation, chlorophyll retention and anthocyanin accumulation. In contrast, overexpressors showed a tendency of less sensitive cytokinin response in most tests. Furthermore, cytokinin-related genes were investigated for their expression; and the expression levels of AHK3, ARR1, CYP735A2 and LOG2 noticeably changed in ugt76c1 plants, suggesting that plants employ a set of cytokinin regulation mechanisms to coordinate the loss-of-function of UGT76C1. Tissue-specific expression of UGT76C1 showed a high level of expression in germinating seeds and young seedlings. Taken together, our data suggest that the glucosyltransferase UGT76C1 could finely modulate cytokinin responses in planta via N-glucosylation of cytokinins.

Overexpression of glucosyltransferase UGT85A1 influences trans-zeatin homeostasis and trans-zeatin responses likely through O-glucosylation.

Trans-zeatin is a kind of cytokinins that plays a crucial role in plant growth and development. The master trans-zeatin O-glucosyltransferase of Arabidopsis thaliana, UGT85A1, has been previously identified through biochemical approach. To determine the in planta role of UGT85A1 gene, the characterization of transgenic Arabidopsis plants overexpressing UGT85A1 was carried out. Under normal conditions, transgenic Arabidopsis did not display clearly altered phenotypes. A remarkable alteration is that the accumulation level of the trans-zeatin O-glucosides was significantly increased in UGT85A1 overexpressing transgenic Arabidopsis, while other forms of cytokinins kept the similar concentrations compared to the wild type. When treated with exogenously applied trans-zeatin, UGT85A1 overexpressing Arabidopsis showed much less sensitivity to trans-zeatin in primary root elongation and lateral root formation. Meanwhile, the chlorophyll content of detached leaves of transgenic Arabidopsis was much lower than wild type. Studies of spatial-temporal expression patterns showed that UGT85A1 was mainly expressed in the early seedlings and developing seeds. Analysis of subcellular localization suggested that UGT85A1 was localized to cytoplasm and nucleus. Taken together, our data suggest that overexpression of Arabidopsis glucosyltransferase UGT85A1 influences trans-zeatin homeostasis and trans-zeatin responses likely through O-glucosylation in planta.

N-glucosyltransferase UGT76C2 is involved in cytokinin homeostasis and cytokinin response in Arabidopsis thaliana.

Cytokinins are a class of phytohormones that play a crucial role in plant growth and development. The gene UGT76C2 encoding cytokinin N-glucosyltransferase of Arabidopsis thaliana has been previously identified. To determine the in planta role of UGT76C2 in cytokinin metabolism and response, we analyzed the phenotypes of its loss-of-function mutant (ugt76c2) and its overexpressors. The accumulation level of the cytokinin N-glucosides was significantly decreased in ugt76c2, but substantially increased in UGT76C2 overexpressors compared with the wild type. When treated with exogenously applied cytokinin, ugt76c2 showed more sensitivity and UGT76C2 overexpressors showed less sensitivity to cytokinin in primary root elongation, lateral root formation, Chl retention and anthocyanin accumulation. Under normal growth conditions ugt76c2 had smaller seeds than the wild type, with accompanying lowered levels of active and N-glucosylated cytokinin forms. The expression levels of cytokinin-related genes such as AHK2, AHK3, ARR1, IPT5 and CKX3 were changed in ugt76c2, suggesting homeostatic control of cytokinin activity. Studies of spatiotemporal expression patterns showed that UGT76C2 was expressed at a relatively higher level in the seedling and developing seed. In their entirety, our data, based mainly on this comparison and opposite phenotypes of knockout and overexpressors, strongly suggest that UGT76C2 is involved in cytokinin homeostasis and cytokinin response in planta through cytokinin N-glucosylation.