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Human terminal deoxynucleotidyl transferase (hTdT) is a DNA polymerase that functions to generate diversity in the adaptive immune system. Here, we focus on the function of naturally occurring single-nucleotide polymorphisms (SNPs) of hTdT to evaluate their role in genetic-generated immune variation. The data demonstrate that the genetic variations generated by the hTdT SNPs will vary the human immune repertoire and thus its responses. Human TdT catalyzes template-independent addition of nucleotides (N-additions) during coding joint formation in V(D)J recombination. Its activity is crucial to the diversity of the antigen receptors of B and T lymphocytes. We used in vitro polymerase assays and in vivo human cell V(D)J recombination assays to evaluate the activity and the N-addition levels of six natural (SNP) variants of hTdT. In vitro, the variants differed from wild-type hTdT in polymerization ability with four having significantly lower activity. In vivo, the presence of TdT varied both the efficiency of recombination and N-addition, with two variants generating coding joints with significantly fewer N-additions. Although likely heterozygous, individuals possessing these genetic changes may have less diverse B- and T-cell receptors that would particularly effect individuals prone to adaptive immune disorders, including autoimmunity.

Tao Han,1,* Zhaozhe Liu,1,* Hengyu Li,2,* Wanqing Xie,3,* Ranran Zhang,1 Li Zhu,2 Fang Guo,1 Yaling Han,4 Yuan Sheng,2 Xiaodong Xie11Department of Oncology, Cancer Center of People’s Liberation Army, General Hospital of Shenyang Military Region, Shenyang, People’s Republic of China; 2Department of Thyroid and Breast Surgery, Changhai Hospital, Second Military Medical University, Shanghai, People’s Republic of China; 3Liaoning University of Traditional Chinese Medicine, Shenyang, People’s Republic of China; 4Department of Cardiology, Institute of Cardiovascular Research of People’s Liberation Army, General Hospital of Shenyang Military Region, Shenyang, People’s Republic of China*These authors contributed equally to this workBackground: Triple-negative breast cancer (TNBC) is a heterogeneous subtype of breast cancer that is prone to recurrence and metastasis with worse prognosis. Epirubicin-based chemotherapy is of great importance for patients with TNBC, but resistance to epirubicin severely limits the application of this drug and this has emerged as a major problem in the treatment of TNBC. The ubiquitin protein D (UBD) molecule has often been considered a tumor oncogene, and has been shown to promote the recurrence and metastasis of malignant tumor cells. Since the role of UBD in epirubicin resistance and its prognostic value in TNBC have not been reported, the study reported here was designed to identify the epirubicin-resistance molecule and clarify the related biomarker for TNBC prognosis.Methods: UBD plasmid was transfected into MDA-MB-231 cells, and the cells were exposed to epirubicin to observe the ability of UBD in epirubicin resistance. UBD expression was also detected in 78 breast cancer tissues by immunohistochemistry. Statistical methods were used to study the relationship between UBD expression and epirubicin resistance in TNBC treatment. Kaplan–Meier survival analysis was used to determine the correlation between UBD expression and TNBC patients’ prognostic parameters.Results: UBD expression was found increased in breast cancer tissues. Forced UBD expression was found to have a relationship with TNBC epirubicin resistance in vitro. High expression of UBD was found in TNBC, compared with in non-TNBC, and this played a positive role in epirubicin resistance and indicated the poor prognosis of TNBC treatment.Conclusion: UBD may play an important role in epirubicin resistance in TNBC. UBD has the potential to be a novel biomarker in TNBC chemoresistance and may be a promising therapeutic target for TNBC patients.Keywords: prognosis, chemoresistance, biomarker

Pertussis-like toxins are secreted by several bacterial pathogens during infection. They belong to the AB5 virulence factors, which bind to glycans on host cell membranes for internalization. Host cell recognition and internalization are mediated by toxin B subunits sharing a unique pentameric ring-like assembly. Although the role of pertussis toxin in whooping cough is well-established, pertussis-like toxins produced by other bacteria are less studied, and their mechanisms of action are unclear. Here, we report that some extra-intestinal Escherichia coli pathogens (i.e. those that reside in the gut but can spread to other bodily locations) encode a pertussis-like toxin that inhibits mammalian cell growth in vitro. We found that this protein, EcPlt, is related to toxins produced by both nontyphoidal and typhoidal Salmonella serovars. Pertussis-like toxins are secreted as disulfide-bonded heterohexamers in which the catalytic ADP-ribosyltransferase subunit is activated when exposed to the reducing environment in mammalian cells. We found here that the reduced EcPlt exhibits large structural rearrangements associated with its activation. We noted that inhibitory residues tethered within the NAD+-binding site by an intramolecular disulfide in the oxidized state dissociate upon the reduction and enable loop restructuring to form the nucleotide-binding site. Surprisingly, although pertussis toxin targets a cysteine residue within the α subunit of inhibitory trimeric G-proteins, we observed that activated EcPlt toxin modifies a proximal lysine/asparagine residue instead. In conclusion, our results reveal the molecular mechanism underpinning activation of pertussis-like toxins, and we also identified differences in host target specificity.

Activation of the relaxin receptor RXFP1 has been associated with improved survival in acute heart failure. ML290 is a small molecule RXFP1 agonist with simple structure, long half-life and high stability. Here we demonstrate that ML290 is a biased agonist in human cells expressing RXFP1 with long-term beneficial actions on markers of fibrosis in human cardiac fibroblasts (HCFs). ML290 did not directly compete with orthosteric relaxin binding and did not affect binding kinetics, but did increase binding to RXFP1. In HEK-RXFP1 cells, ML290 stimulated cAMP accumulation and p38MAPK phosphorylation but not cGMP accumulation or ERK1/2 phosphorylation although prior addition of ML290 increased p-ERK1/2 responses to relaxin. In human primary vascular endothelial and smooth muscle cells that endogenously express RXFP1, ML290 increased both cAMP and cGMP accumulation but not p-ERK1/2. In HCFs, ML290 increased cGMP accumulation but did not affect p-ERK1/2 and given chronically activated MMP-2 expression and inhibited TGF-β1-induced Smad2 and Smad3 phosphorylation. In vascular cells, ML290 was 10x more potent for cGMP accumulation and p-p38MAPK than for cAMP accumulation. ML290 caused strong coupling of RXFP1 to Gαs and GαoB but weak coupling to Gαi3. ML290 exhibited signalling bias at RXFP1 possessing a signalling profile indicative of vasodilator and anti-fibrotic properties.

Deep Convolutional Neural Networks (DCNN) require millions of labeled training examples for image classification and object detection tasks, which restrict these models to domains where such datasets are available. In this paper, we explore the use of unsupervised sparse coding applied to stereo-video data to help alleviate the need for large amounts of labeled data. We show that replacing a typical supervised convolutional layer with an unsupervised sparse-coding layer within a DCNN allows for better performance on a car detection task when only a limited number of labeled training examples is available. Furthermore, the network that incorporates sparse coding allows for more consistent performance over varying initializations and ordering of training examples when compared to a fully supervised DCNN. Finally, we compare activations between the unsupervised sparse-coding layer and the supervised convolutional layer, and show that the sparse representation exhibits an encoding that is depth selective, whereas encodings from the convolutional layer do not exhibit such selectivity. These result indicates promise for using unsupervised sparse-coding approaches in real-world computer vision tasks in domains with limited labeled training data.

The ubiquitous lakes across China's Yangtze Plain (YP) are indispensable freshwater resources sustaining ecosystems and socioeconomics for nearly half a billion people. Our recent survey revealed a widespread net decline in the total YP lake inundation area during 2000–2011 (a cumulative decrease of ∼10%), yet its mechanism remains contentious. Here, we uncover the impacts of climate variability and anthropogenic activities including i) Yangtze flow and sediment alterations by the Three Gorges Dam (TGD) and ii) human water consumption in agricultural, industrial, and domestic sectors throughout the downstream Yangtze Basin. Results suggest that climate variability is the dominant driver of this decadal lake decline, whereas studied human activities, despite varying seasonal impacts that peak in fall, contribute marginal fraction (∼10–20% or less) to the interannual lake area decrease. Given that the TGD impacts on the total YP lake area and its seasonal variation are both under ∼5%, we also dismiss the speculation that the TGD might be responsible for evident downstream climate change by altering lake surface extent and thus open water evaporation. Nevertheless, anthropogenic impacts exhibited a strengthening trend during the past decade. Although the TGD has reached its full-capacity water regulation, the negative impacts of human water consumption and TGD-related net channel erosion are already comparable to that of TGD's flow regulation, and may continue to grow as crucial anthropogenic factors to future YP lake conservation.