No abstract

Adult mammals have lost multi-tissue regenerative capacity, except for the distal digit, which is able to regenerate via mechanisms that remain largely unknown. Here, we show that, after adult mouse distal digit removal, nerve-associated Schwann cell precursors (SCPs) dedifferentiate and secrete growth factors that promote expansion of the blastema and digit regeneration. When SCPs were dysregulated or ablated, mesenchymal precursor proliferation in the blastema was decreased and nail and bone regeneration were impaired. Transplantation of exogenous SCPs rescued these regeneration defects. We found that SCPs secrete factors that promote self-renewal of mesenchymal precursors, and we used transcriptomic and proteomic analysis to define candidate factors. Two of these, oncostatin M (OSM) and platelet-derived growth factor AA (PDGF-AA), are made by SCPs in the regenerating digit and rescued the deficits in regeneration caused by loss of SCPs. As all peripheral tissues contain nerves, these results could have broad implications for mammalian tissue repair and regeneration.

Peripheral nerves provide a supportive growth environment for developing and regenerating axons and are essential for maintenance and repair of many non-neural tissues. This capacity has largely been ascribed to paracrine factors secreted by nerve-resident Schwann cells. Here, we used single-cell transcriptional profiling to identify ligands made by different injured rodent nerve cell types and have combined this with cell-surface mass spectrometry to computationally model potential paracrine interactions with peripheral neurons. These analyses show that peripheral nerves make many ligands predicted to act on peripheral and CNS neurons, including known and previously uncharacterized ligands. While Schwann cells are an important ligand source within injured nerves, more than half of the predicted ligands are made by nerve-resident mesenchymal cells, including the endoneurial cells most closely associated with peripheral axons. At least three of these mesenchymal ligands, ANGPT1, CCL11, and VEGFC, promote growth when locally applied on sympathetic axons. These data therefore identify an unexpected paracrine role for nerve mesenchymal cells and suggest that multiple cell types contribute to creating a highly pro-growth environment for peripheral axons.

No abstract

We have previously demonstrated a high level of stratifin, also known as 14-3-3 sigma in differentiated keratinocyte cell lysate and conditioned medium (CM). In this study, we asked the question of whether other 14-3-3 isoforms are expressed in human dermal fibroblasts, keratinocytes, intact dermal and epidermal layers of skin. In order to address this question, total proteins extracted from cultured cells or skin layers were subjected to western blot analysis using seven different primary antibodies specific to well-known mammalian isoforms, beta, gamma, epsilon, eta, sigma, tau, and zeta of 14-3-3 protein family. The autoradiograms corresponding to each isoform were then quantified and compared. The results revealed the presence of very high levels of all seven isoforms in cultured keratinocyte and conditioned medium. With the exception of tau isoform, other 14-3-3 isoforms were also present in intact epidermal layer of normal skin. The profile of 14-3-3 proteins in whole skin was similar to that of epidermis. In contrast, only gamma 14-3-3 isoform, was present in dermal layer obtained from the same skin sample. On the other hand, cultured fibroblasts express a high level of beta, epsilon, gamma and eta and a low level of zeta and tau, but not sigma isoform. However, the levels of 14-3-3 epsilon, gamma and eta were barely detectable in fibroblast conditioned medium. Further, we also used immunohistochemical staining to identify the 14-3-3 isoform expressing cells in human skin sections. The finding revealed different expression profile for each of these isoforms mainly in differentiated keratinocytes located within the layer of lucidum. However, fibroblasts located within the dermal layer did not show any detectable levels of these proteins. In conclusion, all members of 14-3-3 proteins are expressed by cells of epidermal but not dermal layer of skins and that these proteins are mainly expressed by differentiated keratinocytes.

Convergent and discriminant validity of a generic and a disease-specific instrument to measure quality of life in patients with skin disease. J Invest Dermatol 108:103-7 Nijsten T, Sampogna F, Abeni D (2009) Categorization of Skindex-29 scores using mixture analysis. Dermatology 218:151-4 Prinsen CA, Lindeboom R, Sprangers MA et al. (2010) Health-related quality of life assessment in dermatology: interpretation of Skindex-29 scores using patient-based anchors.

Interaction between keratinocytes and fibroblasts plays a critical role in maintaining skin integrity under both normal and pathological conditions. We have previously demonstrated that keratinocyte-releasable factors influence the expression of key extracellular matrix components, such as collagen and matrix metalloproteinases in dermal fibroblasts. In this study, we utilized DNA microarray analysis to examine the effects of keratinocyte-releasable factors on the expression of several cytokines in human dermal fibroblasts. The results revealed significantly higher granulocyte colony-stimulating factor (G-CSF) expression in fibroblasts co-cultured with keratinocytes relative to mono-cultured cells, which was verified by RT-PCR and western blot. G-CSF is an important hematopoietic factor also thought to play a beneficial role in wound healing through stimulating keratinocyte proliferation. To partially characterize the keratinocyte-releasable factors responsible for stimulating G-CSF production, keratinocyte-conditioned medium (KCM) was subjected to thermal treatment and ammonium sulfate precipitation before treating fibroblasts. The results showed that keratinocyte-releasable G-CSF-stimulating factors remain stable at 56°C and upon 50% ammonium sulfate precipitation. Knowing that keratinocytes release IL-1, which stimulates G-CSF expression in various immune cells, several experiments were conducted to ask whether this might also be the case for fibroblasts. The results showed that the addition of recombinant IL-1 markedly increased G-CSF expression in fibroblasts; however, IL-1 receptor antagonist only partially abrogated KCM-stimulated G-CSF expression, indicating the role of additional keratinocyte-releasable factors. These findings underline the importance of cross-talk between keratinocytes and fibroblasts, suggesting that communication between these cells in vivo modulates the production of cytokines required for cutaneous wound healing and maintenance. J. Cell. Biochem. 118: 308-317, 2017. © 2016 Wiley Periodicals, Inc.

CD4+ T-cell subsets are found in the tumour microenvironment (TME) of low-grade B-cell non-Hodgkin’s lymphomas such as marginal zone lymphoma (MZL) or follicular lymphoma (FL). Both numbers and architecture of activating follicular helper T-cells (Tfh) and suppressive Treg in the TME of FL are associated with clinical outcomes. There has been almost no previous work on CD4+ T-cells in MZL. It is now recognised that circulating CD4+CXCR5+ T-cells are the memory compartment of Tfh cells. We determined differences in number of circulating Tfh (cTfh) cells and cTfh subsets between normal subjects and patients with FL or MZL. Lymphoma patients showed increased numbers of cTfh1 and reduced cTfh17 cells due to decreased expression of the subset-defining marker CCR6 in patients. PD1, a surface marker associated with Tfh cells, showed increased expression on cTfh subsets in patients. Focusing on MZL we determined expression of 96 T-cell associated genes by microfluidic qRT-PCR. Analysis of differentially expressed genes showed significant differences between normal subjects and patients both for bulk cTfh (CCL4) and the cTfh1 subset (JAK3). While our findings require confirmation in larger studies we suggest that analysis of number and gene expression of circulating T-cells might be a source of clinically useful information as is the case for T-cells within lymphoma lymph nodes.