Pathological mechanism and antisense oligonucleotide-mediated rescue of a non-coding variant suppressing factor 9 RNA biogenesis leading to hemophilia B.
- 作者列表："Krooss S","Werwitzke S","Kopp J","Rovai A","Varnholt D","Wachs AS","Goyenvalle A","Aarstma-Rus A","Ott M","Tiede A","Langemeier J","Bohne J
:Loss-of-function mutations in the human coagulation factor 9 (F9) gene lead to hemophilia B. Here, we dissected the consequences and the pathomechanism of a non-coding mutation (c.2545A>G) in the F9 3' untranslated region. Using wild type and mutant factor IX (FIX) minigenes we revealed that the mutation leads to reduced F9 mRNA and FIX protein levels and to lower coagulation activity of cell culture supernatants. The phenotype could not be compensated by increased transcription. The pathomechanism comprises the de novo creation of a binding site for the spliceosomal component U1snRNP, which is able to suppress the nearby F9 poly(A) site. This second, splicing-independent function of U1snRNP was discovered previously and blockade of U1snRNP restored mutant F9 mRNA expression. In addition, we explored the vice versa approach and masked the mutation by antisense oligonucleotides resulting in significantly increased F9 mRNA expression and coagulation activity. This treatment may transform the moderate/severe hemophilia B into a mild or subclinical form in the patients. This antisense based strategy is applicable to other mutations in untranslated regions creating deleterious binding sites for cellular proteins.
: 人凝血因子9 (F9) 基因的功能丧失突变导致血友病B。在这里，我们剖析了F9 3' 非翻译区非编码突变 (c.2545A>G) 的后果和病理机制。使用野生型和突变因子IX (FIX) 小基因，我们揭示了突变导致f9mrna和FIX蛋白水平降低，并降低细胞培养上清液的凝血活性。表型不能通过增加的转录来补偿。病理机制包括重新创建剪接体组分U1snRNP的结合位点，其能够抑制附近的F9 poly (a) 位点。第二，先前发现了U1snRNP的非剪接依赖性功能，并且U1snRNP的阻断恢复了突变体f9mrna的表达。此外，我们探索了反之亦然的方法，并通过反义寡核苷酸掩蔽突变，导致f9mrna表达和凝血活性显著增加。这种治疗可以在患者中将中度/重度血友病B转化为轻度或亚临床形式。这种基于反义的策略适用于在非翻译区中产生细胞蛋白的有害结合位点的其他突变。
METHODS::Vancomycin (VCM) has been reported to elicit adverse cutaneous drug reactions. However, VCM-associated purpuric drug eruption has not been reported yet, except leukocytoclastic vasculitis. A 16-year-old Japanese girl was admitted with a respiratory infection. We initiated intravenous administration of VCM. After the start of treatment, impalpable purpuric eruption appeared on her trunk. The eruption gradually extended to her neck, legs, and arms. Skin biopsy showed vasculitis with lymphocyte infiltration in the superficial dermis. A drug lymphocyte stimulation test yielded positive results for VCM. Her cutaneous symptoms rapidly reversed after the withdrawal of VCM. To the best of our knowledge, this is the first reported case of VCM-associated purpuric drug eruption, which differs from leukocytoclastic vasculitis. We recommend that VCM-associated purpuric drug eruption should be considered in the differential diagnosis during the administration of VCM, and a drug lymphocyte stimulation test may be useful for assessment of pathogenesis.
METHODS::The cardinal biological role of vitamin K is to act as cofactor for the carboxylation of a number of vitamin K-dependent proteins, some of which are essential for coagulation, bone formation and prevention of vascular calcification. Functional vitamin K deficiency is common and severe among dialysis patients and has garnered attention as a modifiable risk factor in this population. However, no single biochemical parameter can adequately assess vitamin K status. For each biological function of vitamin K, the degree of carboxylation of the relevant vitamin K-dependent protein most accurately reflects vitamin K status. Dephosphorylated uncarboxylated matrix Gla protein (dp-ucMGP) is the best biomarker for vascular vitamin K status when cardiovascular endpoints are studied. Dp-ucMGP levels are severely elevated in haemodialysis patients and correlate with markers of vascular calcification and mortality in some but not all studies. The aetiology of vitamin K deficiency in haemodialysis is multifactorial, including deficient intake, uraemic inhibition of the vitamin K cycle and possibly interference of vitamin K absorption by phosphate binders. The optimal vitamin K species, dose and duration of supplementation to correct vitamin K status in dialysis patients are unknown. Dp-ucMGP levels dose-proportionally decrease with supraphysiological vitamin K2 supplementation, but do not normalize even with the highest doses. In the general population, long-term vitamin K1 or K2 supplementation has beneficial effects on cardiovascular disease, bone density and fracture risk, and insulin resistance, although some studies reported negative results. In haemodialysis patients, several trials on the effects of vitamin K on surrogate markers of vascular calcification are currently ongoing.
METHODS::Immune thrombocytopenia (ITP) is an autoimmune disease with a mild to severe risk of bleeding complications. First line treatment includes corticosteroids, immunoglobulins, or other. In this large cohort study, first-line strategies for treatment-naive adult primary ITP was studied in a real-world setting. Records from all adult ITP patients who received first-line treatment between January 2010 and December 2017 at Qilu Hospital were reviewed retrospectively (n = 699). During the study period, 271 patients were treated with high-dose dexamethasone (HDD) and 289 patients were treated with conventional prednisone (alone or in combination with other drugs). Initial responses were similar for the two groups (88.56% vs. 86.51%, P = 0.462), but patients in the HDD group responded earlier than the prednisone group (3 days vs. 5 days, P < 0.001). The sustained response (SR) at 6 months was lower in the HDD group than in the prednisone group (35.4% vs. 47.1%, P = 0.040). However, the SR at 12 months and at the end of our follow-up were not significantly different between the groups. Overall duration of response (DOR) in the prednisone group was longer than in the HDD group throughout the follow-up period (P = 0.007). However, the incidence of SR and overall DOR were not significantly different between the HDD group and the prednisone 3 months group (prednisone terminated within 3 months). The presence of anti-GPIb-IX autoantibodies was a predictive factor for a poor initial response to corticosteroids therapy (P < 0.05). However, neither of the two antiplatelet autoantibodies were correlated with the opportunity to achieve SR and overall DOR in both groups throughout the follow-up period (P > 0.05). Adverse events were more frequent and long-lasting in the prednisone group. Our study showed that HDD provided an effective and more rapid response as initial treatment of ITP, with comparable long-term prognosis and better tolerance when compared with conventional PDN (less than 3 months) in the real-world setting.