Novel mutations in ADAMTS13 CUB domains cause abnormal pre-mRNA splicing and defective secretion of ADAMTS13

Hereditary thrombotic thrombocytopenic purpura (TTP) is an autosomal recessive thrombosis disorder, caused by loss-of-function mutations in ADAMTS13. Mutations in the CUB domains of ADAMTS13 are rare, and the exact mechanisms through which these mutations result in the development of TTP have not yet been fully elucidated. In this study, we identified two novel mutations in the CUB domains in a TTP family with an acceptor splice-site mutation (c.3569−1, G>A, intron 25) and a point missense mutation (c.3923, G>A, exon 28), resulting in a glycine to aspartic acid substitution (p.G1308D). In vitro splicing analysis revealed that the intronic mutation resulted in abnormal pre-mRNA splicing, and an in vitro expression assay revealed that the missense mutation significantly impaired ADAMTS13 secretion. Although both the patient and her brother displayed significantly reduced ADAMTS13 activity and increased levels of ultra-large VWF (ULVWF) multimers in plasma, only the female developed acute episodes of TTP. Our findings indicate the importance of the CUB domains for the protein stability and extracellular secretion of ADAMTS13.     

Serologic Response to SARS-CoV-2 in COVID-19 Patients with Different Severity

Virologica Sinica - The immense patient number caused by coronavirus disease 2019 (COVID-19) global pandemic brings the urge for more knowledge about its immunological features, including the...     

The synthesis and activity evaluation of N‐acylated analogs of echinocandin B with improved solubility and lower toxicity

Presently, echinocandins have been recommended as the first‐line drugs for the treatment of invasive candidiasis. However, low oral bioavailability and solubility limit their application. To improve this situation, this study chose amino acid and fatty acid as raw materials to modify the nucleus of echinocandin B. Six N‐acylated analogs were screened from the derivatives that possessed potent antifungal activity and good water solubility. Based on antifungal susceptibility and hemolytic toxicity, compound 5 as the candidate had good antifungal activity and no hemolytic effect. Moreover, compared with anidulafungin, compound 5 showed a comparable fungicidal effect, much higher solubility, and lower toxicity. In conclusion, compound 5 has the potential for further research and development on account of reserved antifungal activity, high solubility, and low toxicity.     

Protective Effects of 28-O-Caffeoyl Betulin (B-CA) on the Cerebral Cortex of Ischemic Rats Revealed by a NMR-Based Metabolomics Analysis

28-O-caffeoyl betulin (B-CA) has been demonstrated to reduce the cerebral infarct volume caused by transient middle cerebral artery occlusion (MCAO) injury. B-CA is a novel derivative of naturally occurring caffeoyl triterpene with little information associated with its pharmacological target(s). To date no data is available regarding the effect of B-CA on brain metabolism. In the present study, a ¹H-NMR-based metabolomics approach was applied to investigate the therapeutic effects of B-CA on brain metabolism following MCAO in rats. Global metabolic profiles of the cortex in acute period (9 h after focal ischemia onset) after MCAO were compared between the groups (sham; MCAO?+?vehicle; MCAO?+?B-CA). MCAO induced several changes in the ipsilateral cortex of ischemic rats, which consequently led to the neuronal damage featured with the downregulation of NAA, including energy metabolism dysfunctions, oxidative stress, and neurotransmitter metabolism. Treatment with B-CA showed statistically significant rescue effects on the ischemic cortex of MCAO rats. Specifically, treatment with B-CA ameliorated the energy metabolism dysfunctions (back-regulating the levels of succinate, lactate, BCAAs, and carnitine), oxidative stress (upregulating the level of glutathione), and neurotransmitter metabolism disturbances (back-regulating the levels of γ-aminobutyric acid and acetylcholine) associated with the progression of ischemic stroke. With the administration of B-CA, the levels of three phospholipid related metabolites (O-phosphocholine, O-phosphoethanolamine, sn-glycero-3-phosphocholine) and NAA improved significantly. Overall, our findings suggest that treatment with B-CA may provide neuroprotection by augmenting the metabolic changes observed in the cortex following MCAO in rats.

     

Electrospun Scaffold of Collagen and Polycaprolactone Containing ZnO Quantum Dots for Skin Wound Regeneration

Nanofibers(NFs)have been widely used in tissue engineering such as wound healing.In this work,the antibacterial ZnO quantum dots(ZnO QDs)have been incorporated into the biocompatible poly(ε-caprolactone)/collagen(PCL/Col)fibrous scaffolds for wound healing.The as-fabricated PCL-Col/ZnO fibrous scaffolds exhibited good swelling,antibacterial activity,and biodegradation behaviors,which were beneficial for the applications as a wound dressing.Moreover,the PCL-Col/ZnO fibrous scaffolds showed excellent cytocompatibility for promoting cell proliferation.The resultant PCL-Col/ZnO fibrous scaffolds containing vascular endothelial growth factor(VEGF)also exhibited promoted wound-healing effect through promoting expression of transforming growth factor-β(TGF-β)and the vascular factor(CD31)in tissues in the early stages of wound healing.This new electrospun fibrous scaffolds with wound-healing promotion and antibacterial property should be convenient for treating wound healing.     

Characterization of ammonium and nitrate uptake and assimilation in roots of tea plants

It has been pointed out that tea (Camellia sinensis (L.) O. Kuntze) prefers ammonium (NH ₄ ⁺ ) over nitrate (NO ₃ ^? ) as an inorganic nitrogen (N) source. ¹⁵N studies were conducted using hydroponically grown tea plants to clarify the characteristics of uptake and assimilation of NH ₄ ⁺ and NO ₃ ^? by tea roots. The total ¹⁵N was detected, and kinetic parameters were calculated after feeding ¹⁵NH ₄ ⁺ or ¹⁵NO ₃ ^? to tea plants. The process of N assimilation was studied by monitoring the dynamic ¹⁵N abundance in the free amino acids of tea plant roots by GC-MS. Tea plants supplied with ¹⁵NH ₄ ⁺ absorbed significantly more ¹⁵N than those supplied with ¹⁵NO ₃ ^? . The kinetics of ¹⁵NH ₄ ⁺ and ¹⁵NO ₃ ^? influx into tea plants followed a classic biphasic pattern, demonstrating the action of a high affinity transport system (HATS) and a low affinity transport system (LATS). The V _max value for NH ₄ ⁺ uptake was 54.5 nmol/(g dry wt min), which was higher than that observed for NO ₃ ^? (39.3 nmol/(g dry wt min)). K_M estimates were approximately 0.06 mM for NH ₄ ⁺ and 0.16 mM for NO ₃ ^? , indicating a higher rate of NH ₄ ⁺ absorption by tea plant roots. Tea plants fed with ¹⁵NH ₄ ⁺ accumulated larger amounts of assimilated N, especially glutamine (Gln), compared with those fed with ¹⁵NO ₃ ^? . Gln, Glu, theanine (Thea), Ser, and Asp were the main free amino acids that were labeled with ¹⁵N under both conditions. The rate of N assimilation into Thea in the roots of NO ₃ ^? -supplied tea plants was quicker than in NH ₄ ⁺ -supplied tea plants. NO ₃ ^? uptake by roots, rather than reduction or transport within the plant, seems to be the main factor limiting the growth of tea plants supplied with NO ₃ ^? as the sole N source. The NH ₄ ⁺ absorbed by tea plants directly, as well as that produced by NO ₃ ^? reduction, was assimilated through the glutamine synthetase-glutamine oxoglutarate aminotransferase pathway in tea plant roots. The ¹⁵N labeling experiments showed that there was no direct relationship between the Thea synthesis and the preference of tea plants for NH ₄ ⁺ .     

Comparative Study of 1,064-nm Laser-Induced Skin Burn and Thermal Skin Burn

Infrared lasers are widely used in medicine, industry, and other fields. While science, medicine, and the society in general have benefited from the many practical uses of lasers, they also have inherent safety issues. Although several procedures have been put forward to protect the skin from non-specific laser-induced damage, individuals receiving laser therapy or researchers who use laser are still at risk for skin damage. This study aims to understand the interaction between laser and the skin, and to investigate the differences between the skin damage caused by 1,064-nm laser and common thermal burns. Skin lesions on Wistar rats were induced by a 1,064-nm CW laser at a maximum output of 40 W and by a copper brass bar attached to an HQ soldering iron. Histological sections of the lesions and the process of wound healing were evaluated. The widths of the epidermal necrosis and dermal denaturalization of each lesion were measured. To observe wound healing, the epithelial gap and wound gap were measured. Masson’s trichrome and picrosirius red staining were also used to assess lesions and wound healing. The thermal damage induced by laser intensified significantly in both horizontal dimension and in vertical depth with increased duration of irradiation. Ten days after wounding, the dermal injuries induced by laser were more severe. Compared with the laser-induced skin damage, the skin burn induced by an HQ soldering iron did not show a similar development or increased in severity with the passage of time. The results of this study showed the pattern of skin damage induced by laser irradiation and a heated brass bar. This study also highlighted the difference between laser irradiation and thermal burn in terms of skin damage and wound healing, and offers insight for further treatment.