scholarly journals Polycystin-2 Is Required for Chondrocyte Mechanotransduction and Traffics to the Primary Cilium in Response to Mechanical Stimulation

2021 ◽  
Vol 22 (9) ◽  
pp. 4313
Author(s):  
Clare L. Thompson ◽  
Megan McFie ◽  
J. Paul Chapple ◽  
Philip Beales ◽  
Martin M. Knight

Primary cilia and associated intraflagellar transport are essential for skeletal development, joint homeostasis, and the response to mechanical stimuli, although the mechanisms remain unclear. Polycystin-2 (PC2) is a member of the transient receptor potential polycystic (TRPP) family of cation channels, and together with Polycystin-1 (PC1), it has been implicated in cilia-mediated mechanotransduction in epithelial cells. The current study investigates the effect of mechanical stimulation on the localization of ciliary polycystins in chondrocytes and tests the hypothesis that they are required in chondrocyte mechanosignaling. Isolated chondrocytes were subjected to mechanical stimulation in the form of uniaxial cyclic tensile strain (CTS) in order to examine the effects on PC2 ciliary localization and matrix gene expression. In the absence of strain, PC2 localizes to the chondrocyte ciliary membrane and neither PC1 nor PC2 are required for ciliogenesis. Cartilage matrix gene expression (Acan, Col2a) is increased in response to 10% CTS. This response is inhibited by siRNA-mediated loss of PC1 or PC2 expression. PC2 ciliary localization requires PC1 and is increased in response to CTS. Increased PC2 cilia trafficking is dependent on the activation of transient receptor potential cation channel subfamily V member 4 (TRPV4) activation. Together, these findings demonstrate for the first time that polycystins are required for chondrocyte mechanotransduction and highlight the mechanosensitive cilia trafficking of PC2 as an important component of cilia-mediated mechanotransduction.

2020 ◽  
Author(s):  
PR Villamayor ◽  
D Robledo ◽  
C Fernández ◽  
J Gullón ◽  
L Quintela ◽  
...  

ABSTRACTThe vomeronasal organ (VNO) is a chemosensory organ specialized in the detection of pheromones and consequently the regulation of behavioural responses mostly related to reproduction. VNO shows a broad variation on its organization, functionality and gene expression in vertebrates, and although the species analyzed to date have shown very specific features, its expression patterns have only been well-characterized in mice. Despite rabbits represent a model of chemocommunication, unfortunately no genomic studies have been performed on VNO of this species to date. The capacity of VNO to detect a great variety of different stimuli suggests a large number of genes with complex organization to support this function. Here we provide the first comprehensive gene expression analysis of the rabbit VNO through RNA-seq across different sexual maturation stages. We characterized the VNO transcriptome, updating the number of the two main vomeronasal receptor (VR) families, 129 V1R and 70 V2R. Among others, the expression of transient receptor potential channel 2 (TRPC2), a crucial cation channel generating electrical responses to sensory stimulation in vomeronasal neurons, along with the specific expression of some fomyl-peptide receptors and H2-Mv genes, both known to have specific roles in the VNO, revealed a the particular gene expression repertoire of this organ, but also its singularity in rabbits. Moreover, juvenile and adult VNO transcriptome showed consistent differences, which may indicate that these receptors are tuned to fulfill specific functions depending on maturation age. We also identified VNO-specific genes, including most VR and TRPC2, thus confirming their functional association with the VNO. Overall, these results represent the genomic baseline for future investigations which seek to understand the genetic basis of behavioural responses canalized through the VNO.HIGHLIGHTSFirst description of the rabbit vomeronasal organ (VNO) transcriptomeVNO contains a unique gene repertoire depending on the speciesHigh fluctuation of the VNO gene expression reveals changes dependent on age and specific functionsMost vomeronasal-receptors (VR) and transient receptor potential channel 2 (TRPC2) genes are VNO-specificReproduction-related genes shows a wide expression pattern


2021 ◽  
Author(s):  
Elena Conte ◽  
Adele Romano ◽  
Michela De Bellis ◽  
Maria Luisa De Ceglia ◽  
Maria Rosaria Carratù ◽  
...  

We explored the involvement of Oxytocin receptor (Oxtr)/ Transient-receptor-potential-vanilloid-1 (TRPV1) genes and Oxytocin (Oxt) on the adaptation of skeletal muscle to cold stress challenge in mice. Oxtr expression in hypothalamic paraventricular (PVN), supraoptic nuclei (SON), and hippocampus (HIPP) were evaluated by immunohistochemistry in parallel with the measurement of circulating Oxt. The Oxtr and TRPV1 gene expression in Soleus (SOL) and Tibialis Anterior (TA) muscles were investigated by RT-PCR. Histological studies of the cardiac muscle after cold stress were also performed. Male mice (n=15) were divided into controls maintained at room temperature (RT=24°C), exposed to cold stress (CS) at T=4°C for 6 hours (6h), and 5 days (5d). Immunohistochemical studies showed that Oxtr protein expression increased by 2-fold (p=0.01) in PVN and by 1.5-fold (p=0.0001) in HIPP after 6h and 5d CS, but decreased by 2-fold (p=0.026) in SON at 5d. Both Oxtr and TRPV1 gene expression increased after 6h and 5d CS in SOL and TA muscles. Oxtr vs TRPV1 gene expression in SOL and TA muscles evaluated by regression analysis was linearly correlated following CS at 6h and 5d but not at control temperature of 24+1°C, supporting the hypothesis of coupling between these genes. The circulating levels of Oxt are unaffected after 6h CS but decreased by 0.2-fold (p=0.0141) after 5d CS. This is the first report that Oxtr and TRPV1 expression are upregulated in response to cold acclimation in skeletal muscle. The up-regulation of Oxtr in PVN and HIPP balances the decrease of circulating Oxt.


2019 ◽  
Vol 20 (7) ◽  
pp. 1767 ◽  
Author(s):  
Takuya Kameda ◽  
Joel Zvick ◽  
Miriam Vuk ◽  
Aleksandra Sadowska ◽  
Wai Kit Tam ◽  
...  

Transient receptor potential (TRP) channels have emerged as potential sensors and transducers of inflammatory pain. The aims of this study were to investigate (1) the expression of TRP channels in intervertebral disc (IVD) cells in normal and inflammatory conditions and (2) the function of Transient receptor potential ankyrin 1 (TRPA1) and Transient receptor potential vanilloid 1 (TRPV1) in IVD inflammation and matrix homeostasis. RT-qPCR was used to analyze human fetal, healthy, and degenerated IVD tissues for the gene expression of TRPA1 and TRPV1. The primary IVD cell cultures were stimulated with either interleukin-1 beta (IL-1β) or tumor necrosis factor alpha (TNF-α) alone or in combination with TRPA1/V1 agonist allyl isothiocyanate (AITC, 3 and 10 µM), followed by analysis of calcium flux and the expression of inflammation mediators (RT-qPCR/ELISA) and matrix constituents (RT-qPCR). The matrix structure and composition in caudal motion segments from TRPA1 and TRPV1 wild-type (WT) and knock-out (KO) mice was visualized by FAST staining. Gene expression of other TRP channels (A1, C1, C3, C6, V1, V2, V4, V6, M2, M7, M8) was also tested in cytokine-treated cells. TRPA1 was expressed in fetal IVD cells, 20% of degenerated IVDs, but not in healthy mature IVDs. TRPA1 expression was not detectable in untreated cells and it increased upon cytokine treatment, while TRPV1 was expressed and concomitantly reduced. In inflamed IVD cells, 10 µM AITC activated calcium flux, induced gene expression of IL-8, and reduced disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) and collagen 1A1, possibly via upregulated TRPA1. TRPA1 KO in mice was associated with signs of degeneration in the nucleus pulposus and the vertebral growth plate, whereas TRPV1 KO did not show profound changes. Cytokine treatment also affected the gene expression of TRPV2 (increase), TRPV4 (increase), and TRPC6 (decrease). TRPA1 might be expressed in developing IVD, downregulated during its maturation, and upregulated again in degenerative disc disease, participating in matrix homeostasis. However, follow-up studies with larger sample sizes are needed to fully elucidate the role of TRPA1 and other TRP channels in degenerative disc disease.


2020 ◽  
Vol 100 (2) ◽  
pp. 725-803 ◽  
Author(s):  
Karel Talavera ◽  
Justyna B. Startek ◽  
Julio Alvarez-Collazo ◽  
Brett Boonen ◽  
Yeranddy A. Alpizar ◽  
...  

The transient receptor potential ankyrin (TRPA) channels are Ca2+-permeable nonselective cation channels remarkably conserved through the animal kingdom. Mammals have only one member, TRPA1, which is widely expressed in sensory neurons and in non-neuronal cells (such as epithelial cells and hair cells). TRPA1 owes its name to the presence of 14 ankyrin repeats located in the NH2 terminus of the channel, an unusual structural feature that may be relevant to its interactions with intracellular components. TRPA1 is primarily involved in the detection of an extremely wide variety of exogenous stimuli that may produce cellular damage. This includes a plethora of electrophilic compounds that interact with nucleophilic amino acid residues in the channel and many other chemically unrelated compounds whose only common feature seems to be their ability to partition in the plasma membrane. TRPA1 has been reported to be activated by cold, heat, and mechanical stimuli, and its function is modulated by multiple factors, including Ca2+, trace metals, pH, and reactive oxygen, nitrogen, and carbonyl species. TRPA1 is involved in acute and chronic pain as well as inflammation, plays key roles in the pathophysiology of nearly all organ systems, and is an attractive target for the treatment of related diseases. Here we review the current knowledge about the mammalian TRPA1 channel, linking its unique structure, widely tuned sensory properties, and complex regulation to its roles in multiple pathophysiological conditions.


2015 ◽  
Vol 308 (12) ◽  
pp. F1386-F1397 ◽  
Author(s):  
Kaori Takayanagi ◽  
Taisuke Shimizu ◽  
Yosuke Tayama ◽  
Akira Ikari ◽  
Naohiko Anzai ◽  
...  

We assessed the expression profile of Mg2+-transporting molecules in obese diabetic rats as a cause of hypermagnesiuric hypomagnesemia, which is involved in the development of insulin resistance, hypertension, and coronary diseases. Kidneys were obtained from male Otsuka Long-Evans Tokushima fatty (OLETF) and Long-Evans Tokushima Otsuka (LETO) obese diabetic rats at the ages of 16, 24, and 34 wk. Expression profiles were studied by real-time PCR and immunohistochemistry together with measurements of urine Mg2+excretion. Urine Mg2+excretion was increased in 24-wk-old OLETF rats and hypomagnesemia was apparent in 34-wk-old OLETF rats but not in LETO rats (urine Mg2+excretion: 0.16 ± 0.01 μg·min−1·g body wt−1in 24-wk-old LETO rats and 0.28 ± 0.01 μg·min−1·g body wt−1in 24-wk-old OLETF rats). Gene expression of transient receptor potential (TRP)M6 was downregulated (85.5 ± 5.6% in 34-wk-old LETO rats and 63.0 ± 3.5% in 34-wk-old OLETF rats) concomitant with Na+-Cl−cotransporter downregulation, whereas the expression of claudin-16 in tight junctions of the thick ascending limb of Henle was not different. The results of the semiquantitative analysis of immunohistochemistry were consistent with these findings (TRPM6: 0.49 ± 0.04% in 16-wk-old LETO rats, 0.10 ± 0.01% in 16-wk-old OLETF rats, 0.52 ± 0.03% in 24-wk-old LETO rats, 0.10 ± 0.01% in 24-wk-old OLETF rats, 0.48 ± 0.02% in 34-wk-old LETO rats, and 0.12 ± 0.02% in 34-wk-old OLETF rats). Gene expression of fibrosis-related proinflammatory cytokines as well as histological changes showed that the hypermagnesiuria-related molecular changes and tubulointerstitial nephropathy developed independently. TRPM6, located principally in distal convoluted tubules, appears to be a susceptible molecule that causes hypermagnesiuric hypomagnesemia as a tubulointerstitial nephropathy-independent altered tubular function in diabetic nephropathy.


2007 ◽  
Vol 292 (1) ◽  
pp. C553-C563 ◽  
Author(s):  
Sara Morales ◽  
Amalia Diez ◽  
Antonio Puyet ◽  
Pedro J. Camello ◽  
Cristina Camello-Almaraz ◽  
...  

Transient receptor potential protein family C (TRPC) has been proposed as a candidate for channels involved in capacitative Ca2+ entry (CCE) mechanisms, but the modulation of their gene expression remains unexplored. In this study we show that guinea pig gallbladder smooth muscle contains mRNA encoding TRPC1, TRPC2, TRPC3, and TRPC4 proteins whose abundance depends on cytosolic Ca2+ level ([Ca2+]i). Thus lowering the levels of cellular calcium with the chelators EGTA and BAPTA AM results in a downregulation of TRPC1–TRPC4 gene and protein expression. In contrast, activation of Ca2+ influx through L-type Ca2+ channels and Ca2+ release from intracellular stores induced an increase in TRPC1–TRPC4 mRNA and protein abundance. Activation of Ca2+/calmodulin-dependent kinases (CaMK) and phosphorylation of cAMP-response element binding protein accounts for the increase in TRPC mRNA transcription in response to L-type channel-mediated Ca2+ influx . In addition to this mechanism, activation of TRPC gene expression by intracellular Ca2+ release also involves calcineurin pathway. According to the proposed role for these channels, activation of CCE induced an increase in TRPC1 and TRPC3 mRNA abundance, which depends on the integrity of the calcineurin and CaMK pathways. These findings show for the first time an essential autoregulatory role of Ca2+ in Ca2+ homeostasis at the level of TRPC gene and protein expression.


2016 ◽  
Vol 310 (3) ◽  
pp. F230-F236 ◽  
Author(s):  
Chien-Te Lee ◽  
Hwee-Yeong Ng ◽  
Yueh-Ting Lee ◽  
Li-Wen Lai ◽  
Yeong-Hau H. Lien

Calbindin-D28k (CBD-28k) is a calcium binding protein located in the distal convoluted tubule (DCT) and plays an important role in active calcium transport in the kidney. Loop and thiazide diuretics affect renal Ca and Mg handling: both cause Mg wasting, but have opposite effects on Ca excretion as loop diuretics increase, but thiazides decrease, Ca excretion. To understand the role of CBD-28k in renal Ca and Mg handling in response to diuretics treatment, we investigated renal Ca and Mg excretion and gene expression of DCT Ca and Mg transport molecules in wild-type (WT) and CBD-28k knockout (KO) mice. Mice were treated with chlorothiazide (CTZ; 50 mg·kg−1·day−1) or furosemide (FSM; 30 mg·kg−1·day−1) for 3 days. To avoid volume depletion, salt was supplemented in the drinking water. Urine Ca excretion was reduced in WT, but not in KO mice, by CTZ. FSM induced similar hypercalciuria in both groups. DCT Ca transport molecules, including transient receptor potential vanilloid 5 (TRPV5), TRPV6, and CBD-9k, were upregulated by CTZ and FSM in WT, but not in KO mice. Urine Mg excretion was increased and transient receptor potential subfamily M, member 6 (TRPM6) was upregulated by both CTZ and FSM in WT and KO mice. In conclusion, CBD-28k plays an important role in gene expression of DCT Ca, but not Mg, transport molecules, which may be related to its being a Ca, but not a Mg, intracellular sensor. The lack of upregulation of DCT Ca transport molecules by thiazides in the KO mice indicates that the DCT Ca transport system is critical for Ca conservation by thiazides.


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