scholarly journals Myeloid-to-mesenchymal NGF-p75 signaling coordinates skeletal cell migration during repair

2021 ◽  
Author(s):  
Jiajia Xu ◽  
Zhao Li ◽  
Robert J. Tower ◽  
Stefano Negri ◽  
Yiyun Wang ◽  
...  

Tissue repair relies on the coordination of mesenchymal precursor cells (MPCs) which migrate into the injury site, along with the invasion of blood vessels and sensory nerves. Our prior observations found that the neurotrophin Nerve growth factor (NGF) regulates sensory nerve ingrowth to skeletal repair sites via its high-affinity receptor. A body of work in cancer biology suggest that neurotrophins also engage their low-affinity receptor p75 to mediate cellular migration. Here, we observed conditional deletion of p75 in MPCs or osteoblasts to disrupt bone repair independent of neurovascular ingrowth. Single cell sequencing identified defects in migration and wound healing among MPC populations. Deletion of Ngf among myeloid cells phenocopied p75 conditional deletion animals. In vitro studies confirmed a myeloid-to-mesenchymal NGF-p75 axis which operates to induce cellular migration. Together, our data suggest a direct effect of myeloid-derived NGF on progenitor cells, in parallel to sensory nerve recruitment, required for injury repair.

2021 ◽  
Author(s):  
Guo-Xian Pei ◽  
Liu Yang ◽  
Junqin Li ◽  
Bin Liu ◽  
Hao Wu ◽  
...  

Abstract BackgroundGiven the afferent functions, sensors have been found exerting efferent influences and directly alter organ physiology. Sensory nerves have been found critical in osteoclasts and bone resorption. However, the direct evidence of whether sensory nerve efferent influences osteoclast, remains lacking. MethodsWe treated mice with resiniferatoxin (RTX) or complete Freund’s adjuvant (CFA) to induce sensory hypersensitivity. Bone histomorphometry including micro-ct, three-point bending assay, von kossa staining, calcein double labeling, toluidine blue staining, and trap staining were performed to monitor bone quality and bone cells. Multiple virus vectors were applied to trace signals between sensory nerves and osteoclasts. Sensory neurons (SN) and osteoclasts were cocultured to study the effects and mechanisms of the sensory nerves on osteoclasts in vitro. Isobaric tag for relative and absolute quantitation (iTRAQ) was used to identify secreted proteins in the sensory nerve. ResultsHere, we found sensory hypersensitivity significantly increased osteoclast bone resorption; SN directly promote osteoclastogenesis in vitro; and abundant sensory efferent signals transported into osteoclasts. Then our screening identified a novel neuropeptide Peptidyl-prolyl cis-trans isomerase D (Cyp40), is the reverse signal from the sensory nerve and plays a critical role for osteoclastogenesis, via aryl hydrocarbon receptor (AhR)-Ras/Raf-pErk-NFATc1 pathway. The efferent signals from sensory nerves tend to involves in the rapid feedback process: vast majority of sensory efferent signals (87.28%) present in fast-twitch myofibers. ConclusionThis study revealed a novel mechanism of sensory nerves on osteoclasts: the direct promotion of osteoclastogenesis by the Cyp40. This mechanism may represent a direct, and quick response of sensory nerves to the changes in bone. Targeting the Cyp40 could therefore be a strategy to promote bone repair at the early stage of bone injury.


Blood ◽  
1991 ◽  
Vol 78 (4) ◽  
pp. 885-889 ◽  
Author(s):  
R Repp ◽  
T Valerius ◽  
A Sendler ◽  
M Gramatzki ◽  
H Iro ◽  
...  

Abstract Fc receptors are important effector molecules of neutrophilic granulocytes (polymorphonuclear neutrophils [PMN]), connecting phagocytic cells and the specific immune response. Neutrophils from healthy donors express the low-affinity receptors for IgG Fc gamma RII (CD32) and Fc gamma RIII (CD16), but not the high-affinity receptor Fc gamma RI (CD64). The latter has been found on neutrophils from patients with certain bacterial infections and can be induced in vitro after incubation with interferon-gamma. We show here that neutrophils strongly express Fc gamma RI after in vivo application of recombinant human granulocyte colony-stimulating factor (rhG-CSF). PMN from patients receiving rhG-CSF displayed higher cytotoxicity against Daudi lymphoma cells in vitro compared with control patients and with healthy donors. Fab fragments against Fc gamma RII (monoclonal antibody [MoAb] IV.3) inhibited neutrophil-mediated cytotoxicity of healthy donors but not of patients during rhG-CSF therapy. Therefore, expression of Fc receptors by PMN was investigated by flow cytometry and the mean fluorescence intensity (MFI) was compared. After staining with MoAb 32.2 against Fc gamma RL, the median MFI of neutrophils from G-CSF patients (median, 4.78; range, 2.40 to 8.50; n = 5) was significantly higher (P = .002 and P = .001, respectively) than the median MFI of patients not receiving G-CSF (median, 1.23; range, 1.01 to 1.58; n = 6) and the median MFI of healthy donors (median, 1.04; range, 0.67 to 1.12; n = 6). Fc gamma RI disappeared after the discontinuing of the G- CSF injections, but was reinduced during the next treatment cycle with rhG-CSF. The high expression of Fc gamma RI during rhG-CSF therapy correlated with enhanced cytotoxicity. In vitro incubation with rhG-CSF also enhances cytotoxicity, but only minor increments in Fc gamma RI expression were observed. Thus, during in vivo application of rhG-CSF neutrophils acquire an additional potent receptor for mediating tumor cell killing in vitro by induction of the high-affinity receptor for IgG (Fc gamma RI, CD64).


1995 ◽  
Vol 269 (2) ◽  
pp. G203-G209 ◽  
Author(s):  
S. Vanner ◽  
W. K. MacNaughton

This study examined whether capsaicin-sensitive sensory nerves regulate intestinal ion transport using both Ussing chamber and intracellular recording techniques in in vitro submucosal preparations from the guinea pig ileum. In Ussing chamber studies, serosal application of capsaicin (20 nM-20 microM) evoked a biphasic dose-dependent increase in short-circuit current (Isc) (maximal effective concentration 200 nM and 2 microM, respectively). In chloride-free buffer, capsaicin responses were significantly reduced. Capsaicin evoked little or no response when extrinsic sensory nerve fibers had been surgically removed and tetrodotoxin and low-calcium and high-magnesium solutions blocked responses to capsaicin. In epithelial preparations devoid of submucosal neurons, capsaicin had virtually no effect, suggesting that responses evoked by capsaicin-sensitive nerves result from activation of submucosal secretomotor neurons. Intracellular recordings from single submucosal neurons demonstrated that superfusion with capsaicin (2 microM) depolarized neurons with an associated decreased conductance. Depolarizations were completely desensitized when capsaicin was reapplied, but synaptic inputs were unaffected. This study suggests that capsaicin-sensitive nerves can regulate ion transport in the gastrointestinal tract by release of neurotransmitter(s) that activate submucosal secretomotor neurons.


Blood ◽  
2005 ◽  
Vol 105 (11) ◽  
pp. 4321-4329 ◽  
Author(s):  
Paolo Conrotto ◽  
Donatella Valdembri ◽  
Simona Corso ◽  
Guido Serini ◽  
Luca Tamagnone ◽  
...  

Abstract Semaphorins, a large family of membrane-bound and secreted proteins, signal through their transmembrane receptors, the plexins. Semaphorins and plexins share structural homologies with scatter factor receptors, a family of tyrosine kinase receptors for which Met is the prototype. Semaphorins have been studied primarily in the developing nervous system, where they act as repelling cues in axon guidance. However, they are widely expressed in several tissues, and their role in epithelial morphogenesis has been recently established. Not much is known about their role in angiogenesis, a key step during embryonic development and adulthood. Here we demonstrate that a semaphorin, Sema4D, is angiogenic in vitro and in vivo and that this effect is mediated by its high-affinity receptor, Plexin B1. Moreover, we prove that biologic effects elicited by Plexin B1 require coupling and activation of the Met tyrosine kinase. In sum, we identify a proangiogenic semaphorin and provide insight about the signaling machinery exploited by Plexin B1 to control angiogenesis.


Blood ◽  
1991 ◽  
Vol 78 (4) ◽  
pp. 885-889 ◽  
Author(s):  
R Repp ◽  
T Valerius ◽  
A Sendler ◽  
M Gramatzki ◽  
H Iro ◽  
...  

Fc receptors are important effector molecules of neutrophilic granulocytes (polymorphonuclear neutrophils [PMN]), connecting phagocytic cells and the specific immune response. Neutrophils from healthy donors express the low-affinity receptors for IgG Fc gamma RII (CD32) and Fc gamma RIII (CD16), but not the high-affinity receptor Fc gamma RI (CD64). The latter has been found on neutrophils from patients with certain bacterial infections and can be induced in vitro after incubation with interferon-gamma. We show here that neutrophils strongly express Fc gamma RI after in vivo application of recombinant human granulocyte colony-stimulating factor (rhG-CSF). PMN from patients receiving rhG-CSF displayed higher cytotoxicity against Daudi lymphoma cells in vitro compared with control patients and with healthy donors. Fab fragments against Fc gamma RII (monoclonal antibody [MoAb] IV.3) inhibited neutrophil-mediated cytotoxicity of healthy donors but not of patients during rhG-CSF therapy. Therefore, expression of Fc receptors by PMN was investigated by flow cytometry and the mean fluorescence intensity (MFI) was compared. After staining with MoAb 32.2 against Fc gamma RL, the median MFI of neutrophils from G-CSF patients (median, 4.78; range, 2.40 to 8.50; n = 5) was significantly higher (P = .002 and P = .001, respectively) than the median MFI of patients not receiving G-CSF (median, 1.23; range, 1.01 to 1.58; n = 6) and the median MFI of healthy donors (median, 1.04; range, 0.67 to 1.12; n = 6). Fc gamma RI disappeared after the discontinuing of the G- CSF injections, but was reinduced during the next treatment cycle with rhG-CSF. The high expression of Fc gamma RI during rhG-CSF therapy correlated with enhanced cytotoxicity. In vitro incubation with rhG-CSF also enhances cytotoxicity, but only minor increments in Fc gamma RI expression were observed. Thus, during in vivo application of rhG-CSF neutrophils acquire an additional potent receptor for mediating tumor cell killing in vitro by induction of the high-affinity receptor for IgG (Fc gamma RI, CD64).


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