Uridylation and the SKI complex orchestrate the Calvin cycle of photosynthesis through RNA surveillance of TKL1 in Arabidopsis.

RNA uridylation, catalyzed by terminal uridylyl transferases (TUTases), represents a conserved and widespread posttranscriptional RNA modification in eukaryotes that affects RNA metabolism. In plants, several TUTases, including HEN1 SUPPRESSOR 1 (HESO1) and UTP: RNA URIDYLYLTRANSFERASE (URT1), have been characterized through genetic and biochemical approaches. However, little is known about their physiological significance during plant development. Here, we show that HESO1 and URT1 act cooperatively with the cytoplasmic 3'-5' exoribonucleolytic machinery component SUPERKILLER 2 (SKI2) to regulate photosynthesis through RNA surveillance of the Calvin cycle gene TRANSKETOLASE 1 (TKL1) in Arabidopsis. Simultaneous dysfunction of HESO1, URT1, and SKI2 resulted in leaf etiolation and reduced photosynthetic efficiency. In addition, we detected massive illegitimate short interfering RNAs (siRNAs) from the TKL1 locus in heso1 urt1 ski2, accompanied by reduced TKL1/2 expression and attenuated TKL activities. Consequently, the metabolic analysis revealed that the abundance of many Calvin cycle intermediates is dramatically disturbed in heso1 urt1 ski2. Importantly, all these molecular and physiological defects were largely rescued by the loss-of-function mutation in RNA-DEPENDENT RNA POLYMERASE 6 (RDR6), demonstrating illegitimate siRNA-mediated TKL silencing. Taken together, our results suggest that HESO1- and URT1-mediated RNA uridylation connects to the cytoplasmic RNA degradation pathway for RNA surveillance, which is crucial for TKL expression and photosynthesis in Arabidopsis.

The Change in Fibrinogen is Associated with Outcome in Patients with Acute Ischemic Stroke Treated with Endovascular Thrombectomy.

BACKGROUND: Fibrinogen has been identified as a modulator of the coagulation and inflammatory process. There is uncertainty about the relationship between the dynamic profile of fibrinogen levels and its impact on clinical outcomes in patients with acute ischemic stroke treated with endovascular thrombectomy. METHODS: We consecutively enrolled patients with acute ischemic stroke who underwent endovascular thrombectomy. Fibrinogen was measured on admission and during hospitalization. The change in fibrinogen (Δfibrinogen) was calculated as the highest follow-up fibrinogen minus admission fibrinogen, with a positive Δfibrinogen indicating an increase in fibrinogen level. Functional outcome was assessed by the modified Rankin Scale at 3 months. Poor outcome was defined as modified Rankin Scale > 2. RESULTS: A total of 346 patients were included (mean age 67.4 ± 13.6 years, 52.31% men). The median fibrinogen on admission was 2.77 g/L (interquartile range 2.30-3.39 g/L). The median Δfibrinogen was 1.38 g/L (interquartile range 0.27-2.79 g/L). Hyperfibrinogenemia (> 4.5 g/L) on admission was associated with an increased risk of poor outcome [odds ratio (OR) 5.93, 95% confidence interval (CI) 1.44-24.41, p = 0.014]. There was a possible U-shaped association of Δfibrinogen with outcomes, with an inflection point of - 0.43 g/L (p = 0.04). When Δfibrinogen was < - 0.43 g/L, a higher decrease in fibrinogen (lower Δfibrinogen value) was associated with a higher risk of poor outcome (OR 0.22, 95% CI 0.02-2.48, p = 0.219). When Δfibrinogen was > - 0.43 g/L, the risk of poor outcome increased with increasing fibrinogen (OR 1.27, 95% CI 1.04-1.54, p = 0.016). CONCLUSIONS: In patients with endovascular thrombectomy, hyperfibrinogenemia on admission was associated with poor functional outcomes at 3 months, whereas Δfibrinogen was associated with poor 3-month outcomes in a possible U-shaped manner.

Overexpression of TCP8 delays Arabidopsis flowering through a FLOWERING LOCUS C-dependent pathway.

BACKGROUND: Flowering is a key process in the life cycle of plants. The transition from vegetative to reproductive growth is thus under sophisticated regulation by endogenous and environmental signals. The plant-specific Teosinte Branched 1/Cycloidea/Proliferating Cell Factors (TCP) family transcription factors are involved in many biological processes, but their roles in regulating flowering have not been totally elucidated. RESULTS: We explored the role of Arabidopsis TCP8 in plant development and, especially, in flowering control. Overexpression of TCP8 significantly delayed flowering under both long-day and short-day conditions and dominant repression by TCP8 led to various growth defects. The upregulation of TCP8 led to more accumulated mRNA level of FLOWERING LOCUS C (FLC), a central floral repressor of Arabidopsis. TCP8 functions in an FLC-dependent manner, as TCP8 overexpression in the flc-6 loss-of-function mutant failed to delay flowering. The vernalization treatment could reverse the late flowering phenotype caused by TCP8 overexpression. CONCLUSIONS: Our results provide evidence for a role of TCP8 in flowering control and add to our knowledge of the molecular basis of TCP8 function.

The association between hypertensive angiopathy and cerebral amyloid angiopathy in primary intracerebral hemorrhage.

Objective: To determine the association between the burden of cerebral small vessel disease (CSVD) due to hypertensive angiopathy (HA) and cerebral amyloid angiopathy (CAA) on MRI in patients with primary intracerebral hemorrhage (ICH). Methods: Patients with primary ICH admitted to our center from March 2012 to November 2021 were consecutively enrolled. We used multivariate binary and ordinal regression analyses to assess the association between HA-CSVD burden and CAA-CSVD burden. Lobar cerebral microbleeds (CMBs) were categorized into three level of severity: 0-1, 2-4, and ≥ 5 lobar CMBs. A high CAA-CSVD score was defined as a CAA-CSVD score of ≥3. Results: Overall, 222 participants (mean age 59.88 ± 13.56) were included into analysis. Age and ICH etiology differed among different lobar CMB severity and between the presence and absence of high CAA-CSVD score (all p < 0.05). Positive associations between HA-related markers and both lobar CMB severity and high CAA-CSVD score (p < 0.05 for the presence of lacune, deep CMBs ≥5, the presence of WMH, and HA-CSVD score) were observed in univariate analysis. These associations remained significant after adjusting for age, sex, ICH etiology, and potential vascular risk factors. The distribution of CAA-CSVD score was significantly different between patients with and without CMBs ≥5 (adjusted OR 2.351, 95% CI 1.242-4.455, p = 0.009) after correcting for age, sex, ICH etiology, and vascular risk factors. Conclusion: Our study provides evidence of an association between HA-CSVD and CAA-CSVD in patients with primary ICH, which needs to be verified in future studies.