The extracellular matrix (ECM) provides a precise physical and molecular environment for cell maintenance, self-renewal, and differentiation in the stem cell niche. However, the nature and organization of the ECM niche is not well understood. The adult freshwater planarian Schmidtea mediterranea maintains a large population of multipotent stem cells (neoblasts), presenting an ideal model to study the role of the ECM niche in stem cell regulation. Here we tested the function of 165 planarian homologs of ECM and ECM-related genes in neoblast regulation. We identified the collagen gene family as one with differential effects in promoting or suppressing proliferation of neoblasts. col4-1, encoding a type IV collagen α-chain, had the strongest effect. RNA interference (RNAi) of col4-1 impaired tissue maintenance and regeneration, causing tissue regression. Finally, we provide evidence for an interaction between type IV collagen, the discoidin domain receptor, and neuregulin-7 (NRG-7), which constitutes a mechanism to regulate the balance of symmetric and asymmetric division of neoblasts via the NRG-7/EGFR pathway.

Cutaneous T-cell lymphoma (CTCL) is difficult to diagnose at an early stage. Current diagnostic tools include clinical examination, histomorphologic analysis, immunohistochemistry, flow cytometry of peripheral blood and/or lesional tissue, and evaluation of T-cell receptor (TCR) clonality by gene rearrangement analysis (TCRGR). Advances in genomic sequencing, including high-throughput sequencing (HTS), can be used to identify specific clones of rearranged TCR genes. Even with all of these tools, CTCL can take as long as a decade to definitively diagnose, potentially delaying treatment options and causing patient anxiety. This study aimed to evaluate the performance of the various ancillary testing modalities used to diagnose early-stage CTCL. In a subset of patients the performance of HTS was compared to flow cytometry and conventional TCRGR analysis via polymerase chain reaction (PCR). Fifty-five patients, with a total of 68 skin biopsies and peripheral blood draws, were evaluated using flow cytometry, PCR-TCRGR, and HTS-TCRGR to determine the sensitivity and specificity of each ancillary test. In tissue biopsies, flow cytometry (64%), PCR (71%) and HTS (69%) shared similar sensitivities; flow cytometry had the highest specificity (93%), followed by HTS (86%) and PCR (76.9%). However, flow cytometry and PCR had insufficient DNA quantities in 29 and 15% of the specimens, respectively. Peripheral blood testing was less sensitive than tissue testing (flow cytometry 14%, PCR 41%, HTS 33%); in peripheral blood, HTS was the most specific test (flow cytometry, 70%; PCR, 62.5%; and HTS, 100%). HTS is a highly specific molecular test for identifying CTCL in peripheral blood and skin biopsy specimens; however, our findings suggest a need for a continued search for more sensitive tests for early-stage CTCL.

The majority of mixed epithelial and stromal tumors (MEST) of the kidney are benign entities found in female patients. Malignant MEST of the kidney is an extremely rare entity that often behaves clinically similar to an undifferentiated sarcoma. We report a case of a malignant MEST with synchronous papillary and clear cell renal cell carcinomas (RCCs) in a 61-year-old Caucasian man who presented with an incidental finding of a left renal mass on workup for back pain. The patient underwent a left radical nephrectomy, with histopathology confirming a malignant MEST, intimately associated papillary RCC, and separate adjacent focus of clear cell RCC.

The cornea of the eye differs from other mucosal surfaces in that it lacks a viable bacterial microbiome and by its unusually high density of sensory nerve endings.Here, we explored the role of corneal nerves in preventing bacterial adhesion.Pharmacological and genetic methods were used to inhibit the function of corneal sensory nerves or their associated transient receptor potential cation channels TRPA1 and TRPV1. Impacts on bacterial adhesion, resident immune cells, and epithelial integrity were examined using fluorescent labeling and quantitative confocal imaging. TRPA1/TRPV1 double gene-knockout mice were more susceptible to adhesion of environmental bacteria and to that of deliberatelyinoculated Pseudomonas aeruginosa. Supporting the involvement of TRPA1/ TRPV1-expressing corneal nerves, P. aeruginosa adhesion was also promoted by treatment with bupivacaine, or ablation of TRPA1/TRPV1-expressing nerves using RTX. Moreover, TRPA1/TRPV1-dependent defense was abolished by enucleation which severs corneal nerves. High-resolution imaging showed normal corneal ultrastructure and surface-labeling by wheat-germ agglutinin for TRPA1/ TRPV1 knockout murine corneas, and intact barrier function by absence of fluorescein staining. P. aeruginosa adhering to corneas after perturbation of nerve or TRPA1/TRPV1 function failed to penetrate the surface. Single gene-knockout mice showed roles for both TRPA1 and TRPV1, with TRPA1 −/− more susceptible to P. aeruginosa adhesion while TRPV1 −/− corneas instead accumulated environmental bacteria. Corneal CD45+/CD11c+ cell responses to P. aeruginosa challenge, previously shown to counter bacterial adhesion, also depended on TRPA1/ TRPV1 and sensory nerves. Together, these results demonstrate roles for corneal How to cite this article: Wan SJ, Datta A, Flandrin O, et al. Nerve-associated transient receptor potential ion channels can contribute to intrinsic resistance to bacterial adhesion in vivo.

The scavenging capacity of glycoprotein DMBT1 helps defend mucosal epithelia against microbes. DMBT1 binding to multiple bacterial species involves its conserved Scavenger Receptor Cysteine-Rich (SRCR) domains, localized to a 16-mer consensus sequence peptide, SRCRP2. Previously, we showed that DMBT1 bound Pseudomonas aeruginosa pili, and inhibited twitching motility, a pilus-mediated movement important for virulence. Here, we determined molecular characteristics required for twitching motility inhibition. Heat-denatured DMBT1 lost capacity to inhibit twitching motility and showed reduced pili binding (~40%). Size-exclusion chromatography of Lys-C-digested native DMBT1 showed that only high-Mw fractions retained activity, suggesting involvement of the N-terminal containing repeated SRCR domains with glycosylated SRCR-Interspersed Domains (SIDs). However, individual or pooled consensus sequence peptides (SRCRPs 1 to 7) showed no activity and did not bind P. aeruginosa pili; nor did recombinant DMBT1 (aa 1–220) or another SRCR-rich glycoprotein, CD163. Enzymatic de-N-glycosylation of DMBT1, but not de-O-glycosylation, reduced its capacity to inhibit twitching motility (~57%), without reducing pili binding. Therefore, DMBT1 inhibition of P. aeruginosa twitching motility involves its N-glycosylation, its pili-binding capacity is insufficient, and it cannot be conferred by the SRCR bacteria-binding peptide domain, either alone or mixed with other unlinked SRCRPs, suggesting an additional mechanism for DMBT1-mediated mucosal defense.