Mesenchymal stem/stromal cells (MSCs) are a promising resource for cell-based therapy because of their high immunomodulation ability, tropism towards inflamed and injured tissues, and their easy ...access and isolation. Currently, there are more than 1200 registered MSC clinical trials globally. However, a lack of standardized methods to characterize cell safety, efficacy, and biodistribution dramatically hinders the progress of MSC utility in clinical practice. In this review, we summarize the current state of MSC-based cell therapy, focusing on the systemic safety and biodistribution of MSCs. MSC-associated risks of tumor initiation and promotion and the underlying mechanisms of these risks are discussed. In addition, MSC biodistribution methodology and the pharmacokinetics and pharmacodynamics of cell therapies are addressed. Better understanding of the systemic safety and biodistribution of MSCs will facilitate future clinical applications of precision medicine using stem cells.
Breast cancer, a hormone‐dependent tumour, generally includes four molecular subtypes (luminal A, luminal B, HER2 enriched and triple‐negative) based on oestrogen receptor, progesterone receptor and ...human epidermal growth factor receptor‐2. Multiple hormones in the body regulate the development of breast cancer. Endocrine therapy is one of the primary treatments for hormone‐receptor‐positive breast cancer, but endocrine resistance is the primary clinical cause of treatment failure. Prolactin (PRL) is a protein hormone secreted by the pituitary gland, mainly promoting mammary gland growth, stimulating and maintaining lactation. Previous studies suggest that high PRL levels can increase the risk of invasive breast cancer in women. The expression levels of PRL and PRLR in breast cancer cells and breast cancer tissues are elevated in most ER+ and ER− tumours. PRL activates downstream signalling pathways and affects endocrine therapy resistance by combining with prolactin receptor (PRLR). In this review, we illustrated and summarized the correlations between endocrine therapy resistance in breast cancer and PRL, as well as the pathophysiological mechanisms and clinical practices. The study on PRL and its receptor would help explore reversing endocrine therapy‐resistance for breast cancer.
Carbapenemase-producing Klebsiella pneumoniae causes high mortality owing to the limited therapeutic options available. Here, we investigated an emergent carbapenem-resistant K. pneumoniae strain ...with hypervirulence found among KPC-2-producing strains in Taiwan.
KPC-producing K. pneumoniae strains were collected consecutively from clinical specimens at the Taipei Veterans General Hospital between January 2012 and December 2014. Capsular types and the presence of rmpA/rmpA2 were analysed, and PFGE and MLST performed using these strains. The strain positive for rmpA/rmpA2 was tested in an in vivo mouse lethality study to verify its virulence and subjected to WGS to delineate its genomic features.
A total of 62 KPC-2-producing K. pneumoniae strains were identified; all of these belonged to ST11 and capsular genotype K47. One strain isolated from a fatal case with intra-abdominal abscess (TVGHCRE225) harboured rmpA and rmpA2 genes. This strain was resistant to tigecycline and colistin, in addition to carbapenems, and did not belong to the major cluster in PFGE. TVGHCRE225 exhibited high in vivo virulence in the mouse lethality experiment. WGS showed that TVGHCRE225 acquired a novel hybrid virulence plasmid harbouring a set of virulence genes (iroBCDN, iucABCD, rmpA and rmpA2, and iutA) compared with the classic ST11 KPC-2-producing strain.
We identified an XDR ST11 KPC-2-producing K. pneumoniae strain carrying a hybrid virulent plasmid in Taiwan. Active surveillance focusing on carbapenem-resistant hypervirulent K. pneumoniae strains is necessary, as the threat to human health is imminent.
Triple-negative breast cancer (TNBC) is cancer that tested as negative for estrogen receptors (ER), progesterone receptors (PR), and excess human epidermal growth factor receptor 2 (HER2) protein ...which accounts for 15%-20% of all breast cancer cases. TNBC is considered to be a poorer prognosis than other types of breast cancer, mainly because it involves more aggressive phenotypes that are similar to stem cell-like cancer cells (cancer stem cell, CSC). Thus, targeted treatment of TNBC remains a major challenge in clinical practice. This review article surveys the latest evidence concerning the role of genomic alteration in current TNBC treatment responses, current clinical trials and potential targeting sites, CSC and drug resistance, and potential strategies targeting CSCs in TNBC. Furthermore, the role of insulin-like growth factor 1 receptor (IGF-1R) and nicotinic acetylcholine receptors (nAChR) in stemness expression, chemoresistance, and metastasis in TNBC and their relevance to potential treatments are also discussed and highlighted.
Endometriosis is an estrogen-dependent inflammatory disease that affects up to 10% of women of reproductive age and accounts for up to 50% of female infertility cases. It has been highly associated ...with poorer outcomes of assisted reproductive technology (ART), including decreased oocyte retrieval, lower implantation, and pregnancy rates. A better understanding of the pathogenesis of endometriosis-associated infertility is crucial for improving infertility treatment outcomes. Current theories regarding how endometriosis reduces fertility include anatomical distortion, ovulatory dysfunction, and niche inflammation-associated peritoneal or implantation defects. This review will survey the latest evidence on the role of inflammatory niche in the peritoneal cavity, ovaries, and uterus of endometriosis patients. Nonhormone treatment strategies that target these inflammation processes are also included. Furthermore, mesenchymal stem cell-based therapies are highlighted for potential endometriosis treatment because of their immunomodulatory effects and tropism toward inflamed lesion foci. Potential applications of stem cell therapy in treatment of endometriosis-associated infertility in particular for safety and efficacy are discussed.
Nicotinic acetylcholine receptors (nAChRs) are drug targets for neurological diseases and disorders, but selective targeting of the large number of nAChR subtypes is challenging. Marine cone snail ...α‐conotoxins are potent blockers of nAChRs and some have been engineered to achieve subtype selectivity. This engineering effort would benefit from rapid computational methods able to predict mutational energies, but current approaches typically require high‐resolution experimental structures, which are not widely available for α‐conotoxin complexes. Herein, five mutational energy prediction methods were benchmarked using crystallographic and mutational data on two acetylcholine binding protein/α‐conotoxin systems. Molecular models were developed for six nAChR subtypes in complex with five α‐conotoxins that were studied through 150 substitutions. The best method was a combination of FoldX and molecular dynamics simulations, resulting in a predictive Matthews Correlation Coefficient (MCC) of 0.68 (85 % accuracy). Novel α‐conotoxin mutants designed using this method were successfully validated by experimental assay with improved pharmaceutical properties. This work paves the way for the rapid design of subtype‐specific nAChR ligands and potentially accelerated drug development.
FoldX was benchmarked as the best energy prediction method, and seven accurate molecular models of α‐conotoxin/nAChRs were developed as surrogates for the experimental complexes. The combined use of FoldX and these molecular models emerged as an effective approach to predict α‐conotoxins with improved pharmaceutical properties. Novel α‐conotoxin variants designed by this method were successfully validated by experimental assay.
Dihydroorotase (DHOase) is the third enzyme in the de novo biosynthesis pathway for pyrimidine nucleotides, and an attractive target for potential anticancer chemotherapy. By screening plant extracts ...and performing GC-MS analysis, we identified and characterized that the potent anticancer drug plumbagin (PLU), isolated from the carnivorous plant
, was a competitive inhibitor of DHOase. We also solved the complexed crystal structure of yeast DHOase with PLU (PDB entry 7CA1), to determine the binding interactions and investigate the binding modes. Mutational and structural analyses indicated the binding of PLU to DHOase through loop-in mode, and this dynamic loop may serve as a drug target. PLU exhibited cytotoxicity on the survival, migration, and proliferation of 4T1 cells and induced apoptosis. These results provide structural insights that may facilitate the development of new inhibitors targeting DHOase, for further clinical anticancer chemotherapies.
PriB is a primosomal protein required for the replication fork restart in bacteria. Although PriB shares structural similarity with SSB, they bind ssDNA differently. SSB consists of an N-terminal ...ssDNA-binding/oligomerization domain (SSBn) and a flexible C-terminal protein–protein interaction domain (SSBc). Apparently, the largest difference in structure between PriB and SSB is the lack of SSBc in PriB. In this study, we produced the chimeric PriB-SSBc protein in which Klebsiella pneumoniae PriB (KpPriB) was fused with SSBc of K. pneumoniae SSB (KpSSB) to characterize the possible SSBc effects on PriB function. The crystal structure of KpSSB was solved at a resolution of 2.3 Å (PDB entry 7F2N) and revealed a novel 114-GGRQ-117 motif in SSBc that pre-occupies and interacts with the ssDNA-binding sites (Asn14, Lys74, and Gln77) in SSBn. As compared with the ssDNA-binding properties of KpPriB, KpSSB, and PriB-SSBc, we observed that SSBc could significantly enhance the ssDNA-binding affinity of PriB, change the binding behavior, and further stimulate the PriA activity (an initiator protein in the pre-primosomal step of DNA replication), but not the oligomerization state, of PriB. Based on these experimental results, we discuss reasons why the properties of PriB can be retrofitted when fusing with SSBc.
Background and Aims
PreS mutants of HBV have been reported to be associated with HCC. We conducted a longitudinal study of the role of HBV preS mutations in the development of HCC, particularly in ...patients with chronic hepatitis B (CHB) having low HBV DNA or alanine aminotransferase (ALT) levels, and investigated the effects of secretion‐defective preS2 deletion mutant (preS2ΔMT) on hepatocyte damage in vitro and liver fibrosis in vivo.
Approach and Results
Association of preS mutations with HCC in 343 patients with CHB was evaluated by a retrospective case–control follow‐up study. Effects of preS2ΔMT on HBsAg retention, endoplasmic reticulum (ER) stress, calcium accumulation, mitochondrial dysfunction, and liver fibrosis were examined. Multivariate analysis revealed a significant association of preS mutations with HCC (HR, 3.210; 95% CI, 1.072‐9.613; P = 0.037) including cases with low HBV DNA or ALT levels (HR, 2.790; 95% CI, 1.133‐6.873; P = 0.026). Antiviral therapy reduced HCC risk, including cases with preS mutations. PreS2ΔMT expression promoted HBsAg retention in the ER and unfolded protein response (UPR). Transmission electron microscopic examination, MitoTracker staining, real‐time ATP assay, and calcium staining of preS2ΔMT‐expressing cells revealed aberrant ER and mitochondrial ultrastructure, reduction of mitochondrial membrane potential and ATP production, and calcium overload. Serum HBV secretion levels were ~100‐fold lower in preS2ΔMT‐infected humanized Fah–/–/ Rag2–/–/Il2rg–/– triple knockout mice than in wild‐type HBV‐infected mice. PreS2ΔMT‐infected mice displayed up‐regulation of UPR and caspase‐3 and enhanced liver fibrosis.
Conclusions
PreS mutations were significantly associated with HCC development in patients with CHB, including those with low HBV DNA or ALT levels. Antiviral therapy reduced HCC occurrence in patients with CHB, including those with preS mutations. Intracellular accumulation of mutated HBsAg induced or promoted ER stress, calcium overload, mitochondrial dysfunction, impaired energy metabolism, liver fibrosis, and HCC.
αO‐Conotoxin GeXIVA is a 28 amino acid peptide derived from the venom of the marine snail Conus generalis. The presence of four cysteine residues in the structure of GeXIVA allows it to have three ...different disulfide isomers, that is, the globular, ribbon or bead isomer. All three isomers are active at α9α10 nicotinic acetylcholine receptors, with the bead isomer, GeXIVA1,2, being the most potent and exhibiting analgesic activity in animal models of neuropathic pain. The original report of GeXIVA activity failed to observe any effect of the isomers on high voltage‐activated (HVA) calcium channel currents in rat dorsal root ganglion (DRG) neurons. In this study, we report, for the first time, the activity of globular GeXIVA1,3 at G protein‐coupled GABAB receptors (GABABR) inhibiting HVA N‐type calcium (Cav2.2) channels and reducing membrane excitability in mouse DRG neurons. The inhibition of HVA Ba2+ currents and neuroexcitability by GeXIVA1,3 was partially reversed by the selective GABABR antagonist CGP 55845. In transfected HEK293T cells co‐expressing human GABABR1 and R2 subunits and Cav2.2 channels, both GeXIVA1,3 and GeXIVA1,4 inhibited depolarization‐activated Ba2+ currents mediated by Cav2.2 channels, whereas GeXIVA1,2 had no effect. The effects of three cyclized GeXIVA1,4 ribbon isomers were also tested, with cGeXIVA GAG being the most potent at human GABABR‐coupled Cav2.2 channels. Interestingly, globular GeXIVA1,3 also reversibly potentiated inwardly‐rectifying K+ currents mediated by human GIRK1/2 channels co‐expressed with GABABR in HEK293T cells. This study highlights GABABR as a potentially important receptor target for the activity of αO‐conotoxin GeXIVA to mediate analgesia.
αO‐Conotoxin GeXIVA, a peptide derived from the venom of a marine snail, activates GABAB receptors to modulate calcium and potassium channels in pain‐sensing neurons. These receptors are a potentially important target for the activity of αO‐conotoxin GeXIVA to mediate analgesia. Using electrophysiological recording techniques, the activity of different isomers of αO‐GeXIVA was tested on mouse dorsal root ganglion neurons and HEK293T cell lines transfected with human GABAB receptors and Cav2.2 channels or GIRK1/2 channels. This study provides a novel insight into the signalling mechanism of analgesic α‐conotoxins on GABAB receptors.
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