Fine-tuning spatial-temporal dynamics and surface receptor expression support plasma cell-intrinsic longevity.

Durable serological memory following vaccination is critically dependent on the production and survival of long-lived plasma cells (LLPCs). Yet, the factors that control LLPC specification and survival remain poorly resolved. Using intravital two-photon imaging, we find that in contrast to most plasma cells (PCs) in the bone marrow (BM), LLPCs are uniquely sessile and organized into clusters that are dependent on APRIL, an important survival factor. Using deep, bulk RNA sequencing, and surface protein flow-based phenotyping, we find that LLPCs express a unique transcriptome and phenotype compared to bulk PCs, fine-tuning expression of key cell surface molecules, CD93, CD81, CXCR4, CD326, CD44, and CD48, important for adhesion and homing. Conditional deletion of Cxcr4 in PCs following immunization leads to rapid mobilization from the BM, reduced survival of antigen-specific PCs, and ultimately accelerated decay of antibody titer. In naïve mice, the endogenous LLPCs BCR repertoire exhibits reduced diversity, reduced somatic mutations, and increased public clones and IgM isotypes, particularly in young mice, suggesting LLPC specification is non-random. As mice age, the BM PC compartment becomes enriched in LLPCs, which may outcompete and limit entry of new PCs into the LLPC niche and pool.

New insights into the ontogeny, diversity, maturation and survival of long-lived plasma cells.

Plasma cells are unique immune effectors, capable of producing large amounts of high-affinity antibodies that protect against pathogenic infections. Although most plasma cells have short lifespans, certain conditions or vaccinations can give rise to long-lived plasma cells (LLPCs) that provide individuals with lifelong protection against pathogen exposure. The nature of these LLPCs is poorly understood; however, recent studies have shed new light on the ontogeny, diversity, maturation and survival of these unique cells. Whereas LLPCs had been thought to arise preferentially from germinal centres, novel genetic tools have revealed that they can originate from various stages throughout the humoral response. Furthermore, new single-cell analyses have shown that mouse and human plasma cells are heterogeneous and may undergo further maturation in situ in the bone marrow niche. Finally, plasma cells were previously considered to be sessile cells maintained in fixed survival niches, but new data show that plasma cell subsets can differentially migrate and organize into clusters that may be associated with survival niches. These descriptive findings provide new insights into how cell-intrinsic programmes and extrinsic factors may regulate the longevity of plasma cells in various contexts, which suggest new research avenues for their functional validation.

Fine-tuning spatial-temporal dynamics and surface receptor expression support plasma cell-intrinsic longevity.

Durable serological memory following vaccination is critically dependent on the production and survival of long-lived plasma cells (LLPCs). Yet, the factors that control LLPC specification and survival remain poorly resolved. Using intra-vital two-photon imaging, we find that in contrast to most plasma cells in the bone marrow, LLPCs are uniquely sessile and organized into clusters that are dependent on April, an important survival factor. Using deep, bulk RNA sequencing, and surface protein flow-based phenotyping, we find that LLPCs express a unique transcriptome and proteome compared to bulk PCs, fine tuning expression of key cell surface molecules, CD93, CD81, CXCR4, CD326, CD44 and CD48, important for adhesion and homing, and phenotypically label LLPCs within mature PC pool. Conditional deletion of Cxcr4 in PCs following immunization leads to rapid mobilization from the BM, reduced survival of antigen-specific PCs, and ultimately accelerated decay of antibody titer. In naive mice, the endogenous LLPCs BCR repertoire exhibits reduced diversity, reduced somatic mutations, and increased public clones and IgM isotypes, particularly in young mice, suggesting LLPC specification is non-random. As mice age, the BM PC compartment becomes enriched in LLPCs, which may outcompete and limit entry of new PC into the LLPC niche and pool.

Urinary tract foreign body: A case of panurethral and intravesical spray foam insulation.

Foreign bodies are inserted into the genitourinary tract for various reasons, and may present a challenge to remove. We report a case of foam insulation injected into the urethra almost entirely occluding the urethra and filling the bladder. Ultimately both a cystotomy and perineal urethrotomy were required for removal.

Topical rectal antiseptic at time of prostate biopsy: how a resident patient safety project has evolved into institutional practice.

PURPOSE: To report outcomes 5 years after a resident quality initiative incorporated topical rectal antiseptic into our ultrasound-guided prostate needle biopsy (TRUS PNB) protocol. METHODS: A chart review was conducted on 1007 men who underwent TRUS PNB between 2010 and 2017. Comparison groups include those who received a topical rectal antiseptic (N = 437) compared to those who did not (N = 570). Povidone-iodine (N = 303) or 4% chlorhexidine solution without alcohol (N = 134) were topical agents. Outcomes of interest included post-biopsy infection (urinary tract infection and/or sepsis), hospital admission, and need for ICU monitoring. RESULTS: Median age and PSA of men included in this study were 64 years and 12 ng/mL. Almost 90% of patients were Caucasian, 13% had diabetes, 3% were on immunosuppression, 32% had at least one prior biopsy, 14% received antibiotics, and 7% were hospitalized in the past 6 months. 22 patients (2.2%) developed a post-biopsy infection with a significant reduction in the group receiving topical rectal antiseptic (0.8 vs. 3.3%, p = 0.01). Post-biopsy UTI rates (p = 0.04) and hospital admission (p = 0.03) were also lower in the topical antiseptic group with trends to reduction in sepsis and need for ICU monitoring. CONCLUSIONS: What started as a resident quality safety project 5 years ago has demonstrated a reduction in infections and hospital admissions following TRUS PNB. Our institutional practice now routinely uses povidone-iodine or chlorhexidine as an adjunct to oral quinolones for TRUS PNB perioperative prophylaxis.

Evolution of telomere maintenance and tumour suppressor mechanisms across mammals.

Mammalian species differ dramatically in telomere biology. Species larger than 5-10 kg repress somatic telomerase activity and have shorter telomeres, leading to replicative senescence. It has been proposed that evolution of replicative senescence in large-bodied species is an anti-tumour mechanism counteracting increased risk of cancer due to increased cell numbers. By contrast, small-bodied species express high telomerase activity and have longer telomeres. To counteract cancer risk due to longer lifespan, long-lived small-bodied species evolved additional telomere-independent tumour suppressor mechanisms. Here, we tested the connection between telomere biology and tumorigenesis by analysing the propensity of fibroblasts from 18 rodent species to form tumours. We found a negative correlation between species lifespan and anchorage-independent growth. Small-bodied species required inactivation of Rb and/or p53 and expression of oncogenic H-Ras to form tumours. Large-bodied species displayed a continuum of phenotypes requiring additional genetic 'hits' for malignant transformation. Based on these data we refine the model of the evolution of tumour suppressor mechanisms and telomeres. We propose that two different strategies evolved in small and large species because small-bodied species cannot tolerate small tumours that form prior to activation of the telomere barrier, and must instead use telomere-independent strategies that act earlier, at the hyperplasia stage.This article is part of the theme issue 'Understanding diversity in telomere dynamics'.

Comparison of two indices to annotate complications after radical nephroureterectomy.

INTRODUCTION: The Clavien-Dindo (CD) and Comprehensive Complication Index (CCI) are two grading systems that annotate adverse events following surgical procedures. We compare these two classification systems in a cohort of patients undergoing radical nephroureterectomy (RNU). MATERIALS AND METHODS: The charts of 110 consecutive RNU patients were reviewed for complications occurring within 30 days of surgery. Grading by the CD classification system and values for CCI were calculated. Bivariate and multivariate analysis identified associations between perioperative variables and complications, as well as relationship to hospital length of stay. RESULTS: Sixty-seven men and 43 women with a median age of 71, body mass index of 29, estimated glomerular filtration rate (eGFR) of 64 mL/min/1.73 m², and Charlson score of 4 were included. Seventy-five percent underwent a minimally invasive RNU, 47% had a lymph node dissection, and 7% received neoadjuvant chemotherapy. Median hospital length of stay was 4 days (range, 2-22). Overall, 39 patients (35%) experienced a total of 56 complications including 12 major (≥ Clavien III) and 44 minor. Median CCI patients with complications cohort was 20.9 (range, 8.7-100). The upper quartile of CCI (> 75th %) was associated with higher Charlson score (p = 0.03), lower baseline eGFR (p = 0.005), intraoperative transfusion (p = 0.004), and absence of symptoms at presentation (p = 0.015). Major CD complications were associated with these same variables. On multivariate analysis, only the upper quartile of CCI was associated with length of stay (8.25 versus 5.61 days, p < 0.0001) whilst major CD complications were not (7.98 versus 6.32, p = 0.211). CONCLUSIONS: The CCI and CD classification schemes are both associated with similar baseline and perioperative characteristics for RNU patients. However, the cumulative nature of CCI appears to permit more accurate prediction of length of stay following surgery compared to the CD system.

Endoscopic management of upper-tract urothelial carcinoma.

INTRODUCTION: Radical nephroureterectomy with an ipsilateral bladder cuff is the referent standard for management of muscle-invasive, high-grade, or bulky upper-tract urothelial carcinoma (UTUC). Nonetheless, certain patients with UTUC have imperative or elective indications for kidney preservation thereby lending to more conservative strategies for management of this disease. Areas covered: A review of the PubMED and Medline databases was performed to identify original scientific and review articles discussing retrograde ureteroscopic or percutaneous antegrade resection of UTUC tumors published between 1995 and 2016. Comparative studies with radical nephroureterectomy were also included. Expert commentary: Endoscopic ablative treatments via retrograde or antegrade approaches may appropriately treat small, solitary, and low risk UTUC tumors. Recurrences in the ipsilateral upper-tract and bladder distal to the original tumor can occur following nephron-sparing treatments and therefore a vigilant surveillance program with a compliant patient is essential when pursuing this treatment approach.

JNK Phosphorylates SIRT6 to Stimulate DNA Double-Strand Break Repair in Response to Oxidative Stress by Recruiting PARP1 to DNA Breaks.

The accumulation of damage caused by oxidative stress has been linked to aging and to the etiology of numerous age-related diseases. The longevity gene, sirtuin 6 (SIRT6), promotes genome stability by facilitating DNA repair, especially under oxidative stress conditions. Here we uncover the mechanism by which SIRT6 is activated by oxidative stress to promote DNA double-strand break (DSB) repair. We show that the stress-activated protein kinase, c-Jun N-terminal kinase (JNK), phosphorylates SIRT6 on serine 10 in response to oxidative stress. This post-translational modification facilitates the mobilization of SIRT6 to DNA damage sites and is required for efficient recruitment of poly (ADP-ribose) polymerase 1 (PARP1) to DNA break sites and for efficient repair of DSBs. Our results demonstrate a post-translational mechanism regulating SIRT6, and they provide the link between oxidative stress signaling and DNA repair pathways that may be critical for hormetic response and longevity assurance.

Prostate cancer stem cell-targeted efficacy of a new-generation taxoid, SBT-1214 and novel polyenolic zinc-binding curcuminoid, CMC2.24.

BACKGROUND: Prostate cancer is the second leading cause of cancer death among men. Multiple evidence suggests that a population of tumor-initiating, or cancer stem cells (CSCs) is responsible for cancer development and exceptional drug resistance, representing a highly important therapeutic target. The present study evaluated CSC-specific alterations induced by new-generation taxoid SBT-1214 and a novel polyenolic zinc-binding curcuminoid, CMC2.24, in prostate CSCs. PRINCIPAL FINDINGS: The CD133(high)/CD44(high) phenotype was isolated from spontaneously immortalized patient-derived PPT2 cells and highly metastatic PC3MM2 cells. Weekly treatment of the NOD/SCID mice bearing PPT2- and PC3MM3-induced tumors with the SBT-1214 led to dramatic suppression of tumor growth. Four of six PPT2 and 3 of 6 PC3MM2 tumors have shown the absence of viable cells in residual tumors. In vitro, SBT-1214 (100 nM-1 µM; for 72 hr) induced about 60% cell death in CD133(high)/CD44(+/high) cells cultured on collagen I in stem cell medium (in contrast, the same doses of paclitaxel increased proliferation of these cells). The cytotoxic effects were increased when SBT-1214 was combined with the CMC2.24. A stem cell-specific PCR array assay revealed that this drug combination mediated massive inhibition of multiple constitutively up-regulated stem cell-related genes, including key pluripotency transcription factors. Importantly, this drug combination induced expression of p21 and p53, which were absent in CD133(high)/CD44(high) cells. Viable cells that survived this treatment regimen were no longer able to induce secondary spheroids, exhibited significant morphological abnormalities and died in 2-5 days. CONCLUSIONS: We report here that the SBT-1214 alone, or in combination with CMC2.24, possesses significant activity against prostate CD133(high)/CD44(+/high) tumor-initiating cells. This drug combination efficiently inhibits expression of the majority of stem cell-related genes and pluripotency transcription factors. In addition, it induces a previously absent expression of p21 and p53 ("gene wake-up"), which can potentially reverse drug resistance by increasing sensitivity to anti-cancer drugs.