Neutrophil-derived oxidative stress contributes to skin inflammation and scratching in a mouse model of allergic contact dermatitis via triggering pro-inflammatory cytokine and pruritogen production in skin

Allergic contact dermatitis (ACD) is a common skin disease featured with skin inflammation and a mixed itch/pain sensation. The itch/pain causes the desire to scratch, affecting both physical and psychological aspects of patients. Nevertheless, the mechanisms underlying itch/pain sensation of ACD still remain elusive. Here, we found that oxidative stress and oxidation-related injury were remarkably increased in the inflamed skin of a mouse model of ACD. Reducing oxidative stress significantly attenuated itch/pain-related scratching, allokonesis and skin inflammation. RNA-Sequencing reveals oxidative stress contributes to a series of skin biological processes, including inflammation and immune response. Attenuating oxidative stress reduces overproduction of IL-1β and IL-33, two critical cytokines involved in inflammation and pain/itch, in the inflamed skin of model mice. Exogenously injecting H2O2 into the neck skin of naïve mice triggered IL-33 overproduction in skin keratinocytes and induced scratching, which was reduced in mice deficient in IL-33 receptor ST2. ACD model mice showed remarkable neutrophil infiltration in the inflamed skin. Blocking neutrophil infiltration reduced oxidative stress and attenuated scratching and skin inflammation. Therefore, our study reveals a critical contribution of neutrophil-derived oxidative stress to skin inflammation and itch/pain-related scratching of ACD model mice via mechanisms involving the triggering of IL-33 overproduction in skin keratinocytes. Targeting skin oxidative stress may represent an effective therapy for ameliorating ACD.

CXCL5 activates CXCR2 in nociceptive sensory neurons to drive joint pain and inflammation in experimental gouty arthritis

Gouty arthritis evokes joint pain and inflammation. Mechanisms driving gout pain and inflammation remain incompletely understood. Here we show that CXCL5 activates CXCR2 expressed on nociceptive sensory neurons to drive gout pain and inflammation. CXCL5 expression was increased in ankle joints of gout arthritis model mice, whereas CXCR2 showed expression in joint-innervating sensory neurons. CXCL5 activates CXCR2 expressed on nociceptive sensory neurons to trigger TRPA1 activation, resulting in hyperexcitability and pain. Neuronal CXCR2 coordinates with neutrophilic CXCR2 to contribute to CXCL5-induced neutrophil chemotaxis via triggering CGRP- and substance P-mediated vasodilation and plasma extravasation. Neuronal Cxcr2 deletion ameliorates joint pain, neutrophil infiltration and gait impairment in model mice. We confirmed CXCR2 expression in human dorsal root ganglion neurons and CXCL5 level upregulation in serum from male patients with gouty arthritis. Our study demonstrates CXCL5-neuronal CXCR2-TRPA1 axis contributes to gouty arthritis pain, neutrophil influx and inflammation that expands our knowledge of immunomodulation capability of nociceptive sensory neurons.

E2F1-mediated Up-regulation of NCAPG Promotes Hepatocellular Carcinoma Development by Inhibiting Pyroptosis

Background and Aims

As a subunit of the condensin complex, NCAPG has an important role in maintaining chromosome condensation, but its biological function and regulatory mechanism in hepatocellular carcinoma (HCC) remains undefined.

Methods

The prognostic ability of NCAPG in HCC patients was examined by univariate and multivariate Cox regression analysis. ROC curves were plotted to compare the predictive ability of NCAPG and AFP. Double luciferase reporter system, and ChIP were used to investigate transcriptional potential of E2F1 to NCAPG. Pyroptosis was observed by scanning electron microscopy. Protein expression of NCAPG, E2F1, and major proteins constituting NLRP3 inflammasome was determined by western blotting and ELISA. An in vivo tumor formation assay was conducted to verify the in vitro results.

Results

Up-regulated NCAPG was identified in HCC tissues compared with adjacent tissue and high NCAPG was positively correlated with poor prognosis. Serum NCAPG mRNA level was a prognostic factor in HCC patients and also a diagnostic factor with higher predictive ability compared with AFP [AUROC 0.766 (95% CI: 0.650-0.881) vs. 0.649 (95% CI 0.506-0.793)]. HBx transfection resulted in concomitant up-regulation of E2F1 and NCAPG. E2F1 significantly increased the activity of luciferase reporter fused with NCAPG reporter, and the interaction of E2F1 and NCAPG gene was confirmed by ChIP. Silencing of E2F1 resulted in significant down-regulation of NCAPG. Knockdown of NCAPG promote pyroptosis mediated by NLRP3 inflammasome activation in multiple HCC cell lines and also suppressed tumorigenesis in vitro.

Conclusions

We identified a novel role of NCAPG in the regulation of NLRP3 inflammasome-mediated pyroptosis, which was regulated by its upstream transactivator, E2F1. The role of E2F1-NCAPG-NLRP3 regulation of pyroptosis network may be a potential target in HCC treatment.

Activation of Nrf2 antioxidant signaling alleviates gout arthritis pain and inflammation

Excessive deposition of monosodium urate (MSU) crystal in the joint results in gout arthritis, which triggers severe pain and affects life quality. Oxidative stress is a pivotal mechanism that contributes to etiology of gout pain and inflammation. Here we investigated whether activating Nrf2, which plays important roles in regulating endogenous antioxidant response, would attenuate gout arthritis via promoting antioxidant signaling in joint tissues. Gout arthritis model was established by intra-articular injection of MSU (500 μg/ankle) into the right ankle joint of mouse. Pharmacologically activating Nrf2 by activator oltipraz (50, 100 or 150 mg/kg, intraperitoneal) at 1 h before and 5, 23, 47 h after model establishment dose-dependently inhibited joint inflammation, mechanical and heat hypersensitivities in model mice. Oltipraz (100 mg/kg) reversed gait impairments without altering locomotor activity and reduced neutrophil infiltrations in ankle joints. In vitro studies revealed oltipraz (25 μM) inhibited MSU-induced ROS production in mouse macrophages and improved mitochondrial bioenergetics impairments caused by MSU. In vivo ROS imaging combined with biochemical assays confirmed the antioxidant effects of oltipraz on model mice. Nrf2 activation inhibited pro-inflammatory cytokine overproduction in ankle joint and attenuated the overexpression and enhancement in TRPV1 channel in DRG neurons innervating hind limb. Therapeutic effects of oltipraz were abolished by inhibiting Nrf2 or in Nrf2 knockout mice. These results suggest pharmacologically activating Nrf2 alleviates gout pain, gait impairments, inflammation and peripheral sensitization via Nrf2-dependent antioxidant mechanism. Targeting Nrf2 may represent a novel treatment option for gout arthritis.

Electroacupuncture improves gout arthritis pain via attenuating ROS-mediated NLRP3 inflammasome overactivation

BACKGROUND

Gout results from disturbed uric acid metabolism, which causes urate crystal deposition in joints and surrounding tissues. Gout pain management is largely limited to colchicine and nonsteroidal anti-inflammatory drugs. Constant usage of these medications leads to severe side effects. We previously showed electroacupuncture (EA) is effective for relieving pain in animal model of gout arthritis. Here we continued to study the mechanisms underlying how EA alleviates gout pain.

METHODS

Monosodium urate was injected into ankle joint to establish gout arthritis model in mice. EA or sham EA was applied at ST36 and BL60 acupoints of model animals. Biochemical assays, immunostaining, live cell Ca²⁺ imaging and behavioral assays were applied.

RESULTS

Model mice displayed obvious mechanical allodynia, accompanied with gait impairments. EA attenuated mechanical hypersensitivities and improved gait impairments. EA reduced the overexpression of NLRP3 inflammasome signaling molecules in ankle joints of model animals. EA-induced anti-allodynia, as well as inhibition on NLRP3 inflammasome, were mimicked by antagonizing but abolished by activating NLRP3 inflammasome via pharmacological methods. EA attenuated oxidative stress, an upstream signaling of NLRP3 inflammasome in ankle joints of model mice. Exogenously increasing oxidative stress abolished EA's inhibitory effect on NLRP3 inflammasome and further reversed EA's anti-allodynic effect. EA reduced neutrophil infiltrations in ankle joint synovium, a major mechanism contributing to oxidative stress in gout. Pharmacological blocking NLRP3 inflammasome or EA reduced TRPV1 channel overexpression in dorsal root ganglion (DRG) neurons. Ca²⁺ imaging confirmed that EA could reduce functional enhancement in TRPV1 channel in DRG neurons during gout.

CONCLUSIONS

Our results demonstrate that EA reduces gout pain possibly through suppressing ROS-mediated NLRP3 inflammasome activation in inflamed ankle joints and TRPV1 upregulation in sensory neurons, supporting EA as a treatment option for gout pain.

Characterization of pain-related behaviors and gene expression profiling of peripheral sensory ganglia in a mouse model of acute ankle sprain

Introduction

Lateral ankle sprain (LAS) is a very common type of joint injury. It occurred with high incidence among general population and especially among individuals participating sports and outdoor activities. A certain proportion of individuals who once developed LAS may suffer persistent ankle pain that affects daily activities. However, the mechanisms underlying LAS-induced pain still remained largely unknown.

Methods

We established a LAS mouse model and systematically evaluated the pain-related behaviors in this mouse model. RNA sequencing (RNA-Seq), combined with bioinformatics analysis, was undertaken to explore gene expression profiles. Immunostaining was used to study glial cell and neuron activation in ipsilateral spinal cord dorsal horn (SCDH) of LAS model mice. Ibuprofen was used to treat LAS model mice.

Results

The LAS model mice developed obvious signs of mechanical and heat hypersensitivities as well as gait impairments in ipsilateral hind paws. Besides, LAS model mice developed signs of pain-related emotional disorder, including pain-induced aversion. By RNA-Seq, we were able to identify certain differentially expressed genes and signaling pathways that might contribute to pain mechanisms of LAS mouse model. In addition, LAS model mice showed increased c-Fos and p-ERK immunoreactivity as well as astrocyte and microglia overactivation in ipsilateral spinal cord dorsal horn, indicating central sensitization might occur. Finally, LAS model mice respond to ibuprofen, a drug clinically used to treat ankle sprain pain.

Conclusion

Our study found LAS model mice may be used as a preclinical animal model for screening novel targets or therapies for ankle sprain. Thus, the study may further help to understand molecular mechanisms contributing to ankle sprain-induced pain.

CXCL13 contributes to chronic pain of a mouse model of CRPS-I via CXCR5-mediated NF-κB activation and pro-inflammatory cytokine production in spinal cord dorsal horn

BACKGROUND

Complex regional pain syndrome type-I (CRPS-I) causes excruciating pain that affect patients' life quality. However, the mechanisms underlying CRPS-I are incompletely understood, which hampers the development of target specific therapeutics.

METHODS

The mouse chronic post-ischemic pain (CPIP) model was established to mimic CRPS-I. qPCR, Western blot, immunostaining, behavioral assay and pharmacological methods were used to study mechanisms underlying neuroinflammation and chronic pain in spinal cord dorsal horn (SCDH) of CPIP mice.

RESULTS

CPIP mice developed robust and long-lasting mechanical allodynia in bilateral hindpaws. The expression of inflammatory chemokine CXCL13 and its receptor CXCR5 was significantly upregulated in ipsilateral SCDH of CPIP mice. Immunostaining revealed CXCL13 and CXCR5 was predominantly expressed in spinal neurons. Neutralization of spinal CXCL13 or genetic deletion of Cxcr5 (Cxcr5^-/-) significantly reduced mechanical allodynia, as well as spinal glial cell overactivation and c-Fos activation in SCDH of CPIP mice. Mechanical pain causes affective disorder in CPIP mice, which was attenuated in Cxcr5^-/- mice. Phosphorylated STAT3 co-expressed with CXCL13 in SCDH neurons and contributed to CXCL13 upregulation and mechanical allodynia in CPIP mice. CXCR5 coupled with NF-κB signaling in SCDH neurons to trigger pro-inflammatory cytokine gene Il6 upregulation, contributing to mechanical allodynia. Intrathecal CXCL13 injection produced mechanical allodynia via CXCR5-dependent NF-κB activation. Specific overexpression of CXCL13 in SCDH neurons is sufficient to induce persistent mechanical allodynia in naïve mice.

CONCLUSIONS

These results demonstrated a previously unidentified role of CXCL13/CXCR5 signaling in mediating spinal neuroinflammation and mechanical pain in an animal model of CRPS-I. Our work suggests that targeting CXCL13/CXCR5 pathway may lead to novel therapeutic approaches for CRPS-I.

CAF-derived exosomes transmitted Gremlin-1 promotes cancer progression and decreases the sensitivity of hepatoma cells to sorafenib

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies worldwide because of metastasis. An increasing number of studies have reported that cancer-associated fibroblasts (CAFs) have emerged as the largest component of the stroma and play a critical role in tumor-promoting processes. However, the effects of CAFs on cancer progression and the sensitivity of hepatoma cells to sorafenib are not well characterized. Here, we identified the proteome of CAF-derived exosomes, and unveiled that exosomal Gremlin-1 derived from CAFs contributes to epithelial-mesenchymal transition (EMT) of hepatoma cells and the decrease of the sorafenib sensitivity through regulating Wnt/β-catenin and BMP signaling pathways. Compared to control subjects, the level of plasma exosomal Gremlin-1 was significantly increased in HCC patients. Further studies indicated that plasma exosomal Gremlin-1 may predict sorafenib response in HCC patients. Collectively, our findings uncover CAFs-derived Gremlin-1-rich exosomes promote EMT and decrease the sensitivity of hepatoma cells to sorafenib by Wnt/β-catenin and BMP signaling.

Electroacupuncture Ameliorates Mechanical Allodynia of a Rat Model of CRPS-I via Suppressing NLRP3 Inflammasome Activation in Spinal Cord Dorsal Horn Neurons

Complex regional pain syndrome type-I (CRPS-I) is a chronic neurological disorder that results in severe pain and affects patients' life quality. Conventional therapies usually lack effectiveness. Electroacupuncture (EA) is an effective physical therapy for relieving CRPS-I pain. However, the mechanism underlying EA-induced analgesia on CRPS-I still remain unknown. Spinal NLRP3 inflammasome was recently identified to contribute to pain and neuroinflammation in a rat model of CRPS-I by our group. Here, we aimed to study whether EA could inhibit spinal NLRP3 inflammasome activation, thus resulting in pain relief and attenuation of spinal neuroinflammation in the rat model of CRPS-I. We established the rat chronic post-ischemic pain (CPIP) model to mimic CRPS-I. CPIP rats developed remarkable mechanical allodynia that could be relieved by daily EA intervention. NLRP3 inflammasome was activated in spinal cord dorsal horn (SCDH) of CPIP rats, accompanied with over-production of pro-inflammatory cytokine IL-1β. Immunostaining revealed that the cellular distribution of NLRP3 was predominantly located in SCDH neurons. Pharmacological activation of NLRP3 inflammasome per se is sufficient to produce persistent mechanical allodynia in naïve animals, whereas blocking NLRP3 inflammasome attenuates mechanical allodynia of CPIP rats. EA exclusively reduced NLRP3 overexpression in SCDH neurons and attenuated spinal glial cell over-activation in CPIP rats. EA-induced anti-allodynia with attenuation of spinal glial cell over-activation were all mimicked by intrathecal blocking NLRP3 inflammasome and reversed by activating NLRP3 inflammasome, respectively, through pharmacological methods. Finally, spinal blocking IL-1β attenuated mechanical allodynia and spinal glial cell over-activation in CPIP rats, resembling the effects of EA. In all, these results demonstrate that spinal NLRP3 inflammasome activation contributes to mechanical allodynia of the rat model of CRPS-I and EA ameliorates mechanical allodynia through inhibiting NLRP3 inflammasome activation in SCDH neurons. Our study further supports EA can be used as an effective treatment for CRPS-I.

Genome-Wide Expression Profiling by RNA-Sequencing in Spinal Cord Dorsal Horn of a Rat Chronic Postsurgical Pain Model to Explore Potential Mechanisms Involved in Chronic Pain

Background

Chronic postsurgical pain (CPSP) is common among patients receiving major surgeries. CPSP produces suffering in patients, both physically and mentally. However, the mechanisms underlying CPSP remain elusive. Here, a genome-wide expression profiling of ipsilateral spinal cord dorsal horn (SCDH) was performed to identify potential genes related with CPSP.

Methods

A rat skin/muscle incision and retraction (SMIR) model was established to induce CPSP. Immunostaining was used to study glial cell and neuron activation in ipsilateral SCDH of SMIR model rats. RNA sequencing (RNA-Seq), combined with bioinformatics analysis, was undertaken to explore gene expression profiles. qPCR was applied to validate the expression of some representative genes.

Results

The SMIR model rats developed persistent mechanical allodynia in ipsilateral hindpaw for up to 14 days. Ipsilateral SCDH of SMIR rats showed remarkable glial cell and neuron activation. A number of differentially expressed genes (DEGs) were identified in ipsilateral SCDH of SMIR rats by RNA-Seq. qPCR confirmed expression of some representative DEGs. Bioinformatics indicated that chemical synaptic transmission, sensory perception of pain and neuroactive ligand-receptor interaction were predominant functions. We compared our dataset with human pain-related genes and found that several genes exclusively participate in pain modulation and mechanisms.

Conclusion

Our study provided novel understandings of the molecular mechanisms possibly contributing to CPSP. These findings may offer new targets for future treatment of CPSP.

Exploring neuronal mechanisms involved in the scratching behavior of a mouse model of allergic contact dermatitis by transcriptomics

Background

Allergic contact dermatitis (ACD) is a common skin condition characterized by contact hypersensitivity to allergens, accompanied with skin inflammation and a mixed itch and pain sensation. The itch and pain dramatically affects patients’ quality of life. However, still little is known about the mechanisms triggering pain and itch sensations in ACD.

Methods

We established a mouse model of ACD by sensitization and repetitive challenge with the hapten oxazolone. Skin pathological analysis, transcriptome RNA sequencing (RNA-seq), qPCR, Ca²⁺ imaging, immunostaining, and behavioral assay were used for identifying gene expression changes in dorsal root ganglion innervating the inflamed skin of ACD model mice and for further functional validations.

Results

The model mice developed typical ACD symptoms, including skin dryness, erythema, excoriation, edema, epidermal hyperplasia, inflammatory cell infiltration, and scratching behavior, accompanied with development of eczematous lesions. Transcriptome RNA-seq revealed a number of differentially expressed genes (DEGs), including 1436-DEG mRNAs and 374-DEG-long noncoding RNAs (lncRNAs). We identified a number of DEGs specifically related to sensory neuron signal transduction, pain, itch, and neuroinflammation. Comparison of our dataset with another published dataset of atopic dermatitis mouse model identified a core set of genes in peripheral sensory neurons that are exclusively affected by local skin inflammation. We further found that the expression of the pain and itch receptor MrgprD was functionally upregulated in dorsal root ganglia (DRG) neurons innervating the inflamed skin of ACD model mice. MrgprD activation induced by its agonist β-alanine resulted in exaggerated scratching responses in ACD model mice compared with naïve mice.

Conclusions

We identified the molecular changes and cellular pathways in peripheral sensory ganglia during ACD that might participate in neurogenic inflammation, pain, and itch. We further revealed that the pain and itch receptor MrgprD is functionally upregulated in DRG neurons, which might contribute to peripheral pain and itch sensitization during ACD. Thus, targeting MrgprD may be an effective method for alleviating itch and pain in ACD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00316-w.

Gene Expression Profiling of Contralateral Dorsal Root Ganglia Associated with Mirror-Image Pain in a Rat Model of Complex Regional Pain Syndrome Type-I

Background

Mirror-image pain (MIP), which develops from the healthy body region contralateral to the actual injured site, is a mysterious pain phenomenon accompanying many chronic pain conditions, such as complex regional pain syndrome (CRPS). However, the pathogenesis of MIP still remains largely unknown. The purpose of this study is to perform an expression profiling to identify genes related to MIP in an animal model of CRPS-I.

Methods

We established a rat chronic post-ischemic pain (CPIP) model to mimic human CRPS-I. RNA-sequencing (RNA-Seq), bioinformatics, qPCR, immunostaining, and animal behavioral assays were used to screen potential genes in the contralateral dorsal root ganglia (DRG) that may be involved in MIP.

Results

The CPIP model rats developed robust and persistent MIP in contralateral hind paws. Bilateral DRG neurons did not exhibit obvious neuronal damage. RNA-Seq of contralateral DRG from CPIP model rats identified a total 527 differentially expressed genes (DEGs) vs sham rats. The expression changes of several representative DEGs were further verified by qPCR. Bioinformatics analysis indicated that the immune system process, innate immune response, and cell adhesion were among the mostly enriched biological processes, which are important processes involved in pain sensitization, neuroinflammation, and chronic pain. We further identified DEGs potentially involved in pain mechanisms or enriched in small- to medium-sized sensory neurons or TRPV1-lineage nociceptors. By comparing with published datasets summarizing genes enriched in pain mechanisms, we sorted out a core set of genes which might contribute to nociception and the pain mechanism in MIP.

Conclusion

We provided by far the first study to profile gene expression changes and pathway analysis of contralateral DRG for the studying of MIP mechanisms. This work may provide novel insights into understanding the mysterious mechanisms underlying MIP.

IL-33/ST2 induces neutrophil-dependent reactive oxygen species production and mediates gout pain

Objective: Gout, induced by monosodium urate (MSU) crystal deposition in joint tissues, provokes severe pain and impacts life quality of patients. However, the mechanisms underlying gout pain are still incompletely understood.

Methods: We established a mouse gout model by intra-articularly injection of MSU crystals into the ankle joint of wild type and genetic knockout mice. RNA-Sequencing, in vivo molecular imaging, Ca²⁺ imaging, reactive oxygen species (ROS) generation, neutrophil influx and nocifensive behavioral assays, etc. were used.

Results: We found interleukin-33 (IL-33) was among the top up-regulated cytokines in the inflamed ankle. Neutralizing or genetic deletion of IL-33 or its receptor ST2 (suppression of tumorigenicity) significantly ameliorated pain hypersensitivities and inflammation. Mechanistically, IL-33 was largely released from infiltrated macrophages in inflamed ankle upon MSU stimulation. IL-33 promoted neutrophil influx and triggered neutrophil-dependent ROS production via ST2 during gout, which in turn, activated transient receptor potential ankyrin 1 (TRPA1) channel in dorsal root ganglion (DRG) neurons and produced nociception. Further, TRPA1 channel activity was significantly enhanced in DRG neurons that innervate the inflamed ankle via ST2 dependent mechanism, which results in exaggerated nociceptive response to endogenous ROS products during gout.

Conclusions: We demonstrated a previous unidentified role of IL-33/ST2 in mediating pain hypersensitivity and inflammation in a mouse gout model through promoting neutrophil-dependent ROS production and TRPA1 channel activation. Targeting IL-33/ST2 may represent a novel therapeutic approach to ameliorate gout pain and inflammation.

Cancer-associated Fibroblasts induce epithelial-mesenchymal transition via the Transglutaminase 2-dependent IL-6/IL6R/STAT3 axis in Hepatocellular Carcinoma

Cancer-associated fibroblasts (CAFs) play crucial roles in enhancing cell survival, proliferation, invasion, and metastasis. We previously showed that hepatocellular carcinoma-derived CAFs (H-CAFs) promoted proliferation of hepatocellular carcinoma (HCC) cells. This study aimed to further explore the role of CAFs in HCC epithelial-mesenchymal transition (EMT) and the underlying mechanism. High CAF density was significantly associated with liver cirrhosis, inferior clinicopathologic characteristics, elevated EMT-associated markers, and poorer survival in human HCC. Within HCC cells, EMT was induced after co-culture with H-CAFs. Secretomic analysis showed that IL-6 and HGF were the key EMT-stimulating cytokines secreted by H-CAFs. Proteomic analysis revealed that TG2 was significantly upregulated in HCC cells with EMT phenotypes. Overexpression of TG2 promoted EMT of HCC cells, and knockdown of TG2 remarkably attenuated the H-CAF-induced EMT. Furthermore, during EMT, TG2 expression was enhanced after HCC cells were stimulated by IL-6, but not HGF. Inhibition of the IL-6/STAT3 signaling decreased TG2 expression. The principal TG2 transcription control element and a potential STAT3 binding site were identified using promoter analysis. Hence, H-CAFs facilitates HCC cells EMT mediated by IL-6, which in turn activates IL-6/IL6R/STAT3 axis to promote TG2 expression.

Serum exosomal long noncoding RNAs lnc-FAM72D-3 and lnc-EPC1-4 as diagnostic biomarkers for hepatocellular carcinoma

Long noncoding RNAs (lncRNAs), such as LINC00462, HOTAIR, and MALAT1, are significantly upregulated in hepatocellular carcinoma (HCC) tissues. However, lncRNA expression in the serum of HCC patients is still unclear. To identify candidate lncRNAs for HCC diagnosis, we purified exosomal total RNA from the serum of healthy volunteers (controls) and hepatitis, cirrhosis, and HCC patients. To assess the function of lncRNAs, small interfering RNAs and overexpression vectors were designed and cell viability and cell apoptosis assays conducted. The exosomes of the control group had a larger number of lncRNAs with a high amount of alternative splicing compared to hepatic disease patients. qPCR assays showed that lnc-FAM72D-3, lnc-GPR89B-15, lncZEB2-19, and lnc-EPC1-4 are differentially expressed in HCC. Furthermore, the expression level of lnc-EPC1-4 correlated with age. While the expression levels of lnc-GPR89B-15 and lnc-EPC1-4 correlated with serum alpha-fetoprotein level. lnc-FAM72D-3 knockdown decreased cell viability and promoted cell apoptosis, indicating that lnc-FAM72D-3 functions as an oncogene in HCC. In contrast, lnc-EPC1-4 overexpression inhibited cell proliferation and induced cell apoptosis, indicating that it functions as a tumor suppressor gene. Collectively, these findings show that lnc-FAM72D-3 and lnc-EPC1-4 play a novel role that might contribute to hepatocarcinogenesis and identify potential candidate biomarkers for HCC diagnosis.

Expression profiling of spinal cord dorsal horn in a rat model of complex regional pain syndrome type-I uncovers potential mechanisms mediating pain and neuroinflammation responses

BACKGROUND

Complex regional pain syndrome type-I (CRPS-I) is a progressive and devastating pain condition. The mechanisms of CRPS-I still remain poorly understood. We aim to explore expression profiles of genes relevant to pain and neuroinflammation mechanisms involved in CRPS-I.

METHODS

The rat chronic post-ischemic pain (CPIP) model that mimics human CRPS-I was established. RNA-sequencing (RNA-Seq), qPCR, Western blot, immunostaining, and pharmacological studies were used for profiling gene changes in ipsilateral spinal cord dorsal horn (SCDH) of CPIP model rat and further validation.

RESULTS

CPIP rats developed persistent mechanical allodynia in bilateral hind paws, accompanied with obvious glial activation in SCDH. RNA-Seq identified a total of 435 differentially expressed genes (DEGs) in ipsilateral SCDH of CPIP rats. qPCR confirmed the expression of several representative genes. Functional analysis of DEGs identified that the most significantly enriched biological processes of upregulated genes include inflammatory and innate immune response. We further identified NLRP3 inflammasome expression to be significantly upregulated in SCDH of CPIP rats. Pharmacological blocking NLRP3 inflammasome reduced IL-1β overproduction, glial activation in SCDH as well as mechanical allodynia of CPIP rats.

CONCLUSION

Our study revealed that immune and inflammatory responses are predominant biological events in SCDH of CPIP rats. We further identified NLRP3 inflammasome in SCDH as a key contributor to the pain and inflammation responses in CPIP rats. Thus, our study provided putative novel targets that may help to develop effective therapeutics against CRPS-I.

Eucalyptol alleviates inflammation and pain responses in a mouse model of gout arthritis

BACKGROUND AND PURPOSE

Gout arthritis, which is provoked by monosodium urate (MSU) crystal accumulation in the joint and periarticular tissues, induces severe pain and affects quality of life of the patients. Eucalyptol (1,8-cineol), the principal component in the essential oils of eucalyptus leaves, is known to possess anti-inflammatory and analgesic properties. We aimed to examine the therapeutic effects of eucalyptol on gout arthritis and related mechanisms.

EXPERIMENTAL APPROACH

A mouse model of gout arthritis was established via MSU injection into the ankle joint. Ankle oedema, mechanical allodynia, neutrophil infiltration, oxidative stress, NLRP3 inflammasome, and TRPV1 expression were examined.

KEY RESULTS

Eucalyptol attenuated MSU-induced mechanical allodynia and ankle oedema in dose-dependently, with effectiveness similar to indomethacin. Eucalyptol reduced inflammatory cell infiltrations in ankle tissues. Eucalyptol inhibited NLRP3 inflammasome activation and pro-inflammatory cytokine production induced by MSU in ankle tissues in vivo. Eucalyptol reduced oxidative stress induced by MSU in RAW264.7 cells in vitro as well as in ankle tissues in vivo, indicated by an increase in activities of antioxidant enzymes and reduction of ROS. Eucalyptol attenuated MSU-induced up-regulation of TRPV1 expression in ankle tissues and dorsal root ganglion neurons innervating the ankle. The in vivo effects of eucalyptol on ankle oedema, mechanical allodynia, NLRP3 inflammasome, IL-1β, and TRPV1 expression were mimicked by treating MSU-injected mice with antioxidants.

CONCLUSION AND IMPLICATIONS

Eucalyptol alleviates MSU-induced pain and inflammation via mechanisms possibly involving anti-oxidative effect. Eucalyptol and other antioxidants may represent promising therapeutic options for gout arthritis.

Chronic Post-Ischemia Pain Model for Complex Regional Pain Syndrome Type-I in Rats

Complex regional pain syndrome type-I (CRPS-I) is a neurological disease that causes severe pain among patients and remains an unresolved medical condition. However, the underlying mechanisms of CRPS-I have yet to be revealed. It is known that ischemia/reperfusion is one of the leading factors that causes CRPS-I. By means of prolonged ischemia and reperfusion of the hind limb, the rat chronic post-ischemia pain (CPIP) model has been established to mimic CRPS-I. The CPIP model has become a well-recognized animal model for studying the mechanisms of CRPS-I. This protocol describes the detailed procedures involved in the establishment of the rat model of CPIP, including anesthesia, followed by ischemia/reperfusion of the hind limb. Characteristics of the rat CPIP model are further evaluated by measuring the mechanical and thermal hypersensitivities of the hind limb as well as the nocifensive responses to acute capsaicin injection. The rat CPIP model exhibits several CRPS-I-like manifestations, including hind limb edema and hyperemia in the early stage after establishment, persistent thermal and mechanical hypersensitivities, and increased nocifensive responses to acute capsaicin injection. These characteristics render it a suitable animal model for further investigation of the mechanisms involved in CRPS-I.

Transcriptome profiling reveals Th2 bias and identifies endogenous itch mediators in poison ivy contact dermatitis

In the United States, poison ivy is the most common naturally occurring allergen that causes allergic contact dermatitis (ACD). The immune and pruritic mechanisms associated with poison ivy ACD remain largely unexplored. Here, we compared skin whole transcriptomes and itch mediator levels in mouse ACD models induced by the poison ivy allergen, urushiol, and the synthetic allergen, oxazolone. The urushiol model produced a Th2-biased immune response and scratching behavior, resembling findings in poison ivy ACD patients. Urushiol-challenged skin contained elevated levels of the cytokine thymic stromal lymphopoietin (TSLP), a T cell regulator and itch mediator, and pruritogenic serotonin (5-HT) and endothelin (ET-1) but not substance P (SP) or histamine. The oxazolone model generated a mixed Th1/Th2 response associated with increased levels of SP, 5-HT, and ET-1 but not TSLP or histamine. Injections of a TSLP monoclonal neutralizing antibody or serotonergic or endothelin inhibitors, but not SP inhibitors or antihistamines, reduced scratching behaviors in urushiol-challenged mice. Our findings suggest that the mouse urushiol model may serve as a translational model of human poison ivy ACD. Inhibiting signaling by TSLP and other cytokines may represent alternatives to the standard steroid/antihistamine regimen for steroid-resistant or -intolerant patients and in exaggerated systemic responses to poison ivy.

Characterization of the immune and pruritic pathways in a mouse model of poison ivy-induced allergic contact dermatitis.

TRPV1 Channel Contributes to the Behavioral Hypersensitivity in a Rat Model of Complex Regional Pain Syndrome Type 1

Complex regional pain syndrome type 1 (CRPS-I) is a debilitating pain condition that significantly affects life quality of patients. It remains a clinically challenging condition and the mechanisms of CRPS-I have not been fully elucidated. Here, we investigated the involvement of TRPV1, a non-selective cation channel important for integrating various painful stimuli, in an animal model of CRPS-I. A rat model of chronic post-ischemia pain (CPIP) was established to mimic CRPS-I. TRPV1 expression was significantly increased in hind paw tissue and small to medium-sized dorsal root ganglion (DRG) neurons of CPIP rats. CPIP rats showed increased TRPV1 current density and capsaicin responding rate in small-sized nociceptive DRG neurons. Local pharmacological blockage of TRPV1 with the specific antagonist AMG9810, at a dosage that does not produce hyperthermia or affect thermal perception or locomotor activity, effectively attenuated thermal and mechanical hypersensitivity in bilateral hind paws of CPIP rats and reduced the hyperexcitability of DRG neurons induced by CPIP. CPIP rats showed bilateral spinal astrocyte and microglia activations, which were significantly attenuated by AMG9810 treatment. These findings identified an important role of TRPV1 in mediating thermal and mechanical hypersensitivity in a CRPS-I animal model and further suggest local pharmacological blocking TRPV1 may represent an effective approach to ameliorate CRPS-I.

Transcriptome profiling of dorsal root ganglia in a rat model of complex regional pain syndrome type-I reveals potential mechanisms involved in pain

Purpose: Complex regional pain syndrome type-I (CRPS-I) is a progressive and devastating pain condition, which remains clinically challenging. The mechanisms of CRPS-I still remain largely unknown. We aim to identify transcriptome profiles of genes relevant to pain mechanisms and major pathways involved in CRPS-I.

Methods: A rat model of chronic post-ischemia pain (CPIP) was established to mimic CRPS-I. RNA-sequencing (RNA-Seq) was used to profile transcriptome of L4-6 dorsal root ganglia (DRGs) of a rat model of CRPS-I.

Results: CPIP model rats developed persistent mechanical/thermal hyperalgesia in ipsilateral hind paw. RNA-Seq identified a total of 295 differentially expressed genes (DEGs), including 195 up- and 100 downregulated, in ipsilateral DRGs of CPIP rats compared with sham rats. The expression of several representative genes was confirmed by qPCR. Functional analysis of DEGs revealed that the most significant enriched biological processes of upregulated genes include response to lipopolysaccharide, inflammatory response and cytokine activity, which are all important mechanisms mediating pain. We further screened DEGs implicated in pain progress, genes enriched in small- to medium-sized sensory neurons and enriched in TRPV1-lineage nociceptors. By comparing our dataset with other published datasets of neuropathic or inflammatory pain models, we identified a core set of genes and pathways that extensively participate in CPIP and other neuropathic pain states.

Conclusion: Our study identified transcriptome gene changes in DRGs of an animal model of CRPS-I and could provide insights into identifying promising genes or pathways that can be potentially targeted to ameliorate CRPS-I.

ETAR and protein kinase A pathway mediate ET-1 sensitization of TRPA1 channel: A molecular mechanism of ET-1-induced mechanical hyperalgesia

Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor that has been widely known as a pain mediator involved in various pain states. Evidence indicates that ET-1 sensitizes transient receptor potential cation channel, subfamily A, member 1 (TRPA1) in vivo. But the molecular mechanisms still remain unknown. We aim to explore whether ET-1 sensitizes TRPA1 in primary sensory neurons and the molecular mechanisms. Ca2+ imaging, immunostaining, electrophysiology, animal behavioral assay combined with pharmacological experiments were performed. ET-1 sensitized TRPA1-mediated Ca2+ responses in human embryonic kidney (HEK)293 cells as well as in cultured native mouse dorsal root ganglion (DRG) neurons. ET-1 also sensitized TRPA1 channel currents. ET-1 sensitized TRPA1 activated by endogenous agonist H2O2. ETA receptor (ETAR) colocalized with TRPA1 in DRG neurons. ET-1-induced TRPA1 sensitization in vivo was mediated via ETAR and protein kinase A (PKA) pathway in HEK293 cells and DRG neurons. Pharmacological blocking of ETAR, PKA, and TRPA1 significantly attenuated ET-1-induced mechanical hyperalgesia in mice. Our results suggest that TRPA1 acts as a molecular target for ET-1, and sensitization of TRPA1 through ETAR-PKA pathway contributes to ET-1-induced mechanical hyperalgesia. Pharmacological targeting of TRPA1 and ETAR-PKA pathway may provide effective strategies to alleviate pain conditions associated with ET-1.

Involvement of Transient Receptor Potential Cation Channel Member A1 activation in the irritation and pain response elicited by skin-lightening reagent hydroquinone

Hydroquinone (HQ) is one of the most frequently used and effective skin-lightening products to treat skin hyperpigmentation disorders, including postinflammatory hyperpigmentation, melasma and solar lentigines. HQ is also widely used in cosmetic products for skin whitening. However, HQ treatment can evoke substantial skin irritation, a side effect that remains poorly understood. Here we demonstrate that HQ is an activator of the peripheral irritant receptor transient receptor potential (TRP) cation channel member A1 (TRPA1). HQ failed to activate TRPV1, TRPV4 or TRPM8. HQ-induced TRPA1 activation was dependent on essential redox-sensitive cysteine and lysine residues within N-terminus of channel protein. HQ elicited Ca²⁺ influx in a subpopulation of mouse sensory neurons sensitive to the TRPA1 agonist, mustard oil. HQ-induced neuronal responses were significantly reduced by TRPA1 inhibitors, and reduced in neurons isolated from Trpa1-deficient mice. In mice, intraplantar injection of HQ at clinically relevant concentrations elicited both acute pain and persistent mechanical hyperalgesia which were almost completely abolished by TRPA1 inhibitors. These findings identify TRPA1 as a molecular target for HQ and provide insights into the mechanism of HQ-induced skin irritation. These findings also suggest that selective TRPA1 antagonists may be useful to counteract HQ-induced skin irritation.

The expression of HDAC7 in cancerous gastric tissues is positively associated with distant metastasis and poor patient prognosis

PURPOSE

To characterize the expression patterns of HDAC7 in patients with gastric cancer and evaluate the prognostic value of HDAC7 in gastric cancer.

METHODS

The expression of histone deacetylase 7 (HDAC7) was detected in paraffin-embedded gastric cancer samples from 86 patients by immunohistochemistry, and the differences in the expression of HDAC7 between cancerous and corresponding adjacent noncancerous tissues were compared using the Wilcoxon matched-pairs signed rank test. The correlation between HDAC7 expression and Ki-67 expression or clinicopathologic characteristics was evaluated using a Spearman rank correlation test. Prognostic outcomes that correlated with HDAC7 were examined using a Kaplan-Meier analysis and Cox proportional hazards model. Moreover, the effects of HDAC7 on the proliferation, migration and invasion of gastric cancer cells were investigated in vitro using human gastric carcinoma AGS cells.

RESULTS

We found that HDAC7 was downregulated in cancerous gastric tissues (P = 0.0019). However, the expression of HDAC7 in cancerous gastric tissues positively correlated with Ki-67 expression (P = 0.0325) and distant metastasis (P = 0.020). Moreover, overall survival was shorter for patients expressing higher levels of HDAC7 in cancerous tissues (P = 0.042). Mechanistically, the disruption of the HDAC7 gene attenuated the capacity of cell growth, migration and invasion and induced G0/G1 arrest in AGS cells. Conversely, forced ovperexpression of HDAC7 promoted cell growth, migration and invasion and G1/S transition in AGS cells.

CONCLUSIONS

These results indicate that high HDAC7 expression in cancerous gastric tissues correlates with distant metastasis and predicts a poor prognosis for patients with gastric cancer.

Downregulation of miR-33a-5p in Hepatocellular Carcinoma: A Possible Mechanism for Chemotherapy Resistance

Background

Multi-drug resistance is one of the major problems limiting the efficacy of cisplatin (CDDP) in treatment of hepatocellular carcinoma (HCC), and abnormal microRNA (miRNA) expression in drug-resistant cell lines plays an important role in liver cancer chemotherapy resistance.

Material/Methods

We established stable Hep3B and 97L HCC cell strains resistant to CDDP, both in vitro and in vivo. A combination of microRNA microarray and RT-qPCR experiments were used to screen differentially expressed miRNAs in HCC cell strains. A CCK-8 assay was carried out to detect and calculate the survival rates and relative inhibitory rates. Oligonucleotide transfection was used to confirm the regulatory function of the miRNA in HCC drug resistance.

Results

The IC50 of Hep3B/CDDP(v), 97L/CDDP(v), Hep3B/CDDP(s), and 97L/CDDP(s) were significantly higher than that of their parental cells. Moreover, the doubling time of drug-resistant cells increased compared with their parent cells. MiRCURYTM LNA Array (v 16.0) high-throughput tests of resistant cell models and their parent cells showed that there were 5 downregulated microRNAs in the 4 drug-resistant cell lines, and we chose hsa-miR-33a-5p as our target for further study. Oligonucleotide transfection showed that miR-33a-5p overexpression increased the cisplatin sensitivity of Hep3B/CDDP(v) and 97L/CDDP(v) drug-resistant cells and reduced their resistance. Additionally, inhibition of miR-33a-5p expression reduced cisplatin sensitivity in Hep3B and 97L and increased their drug resistance.

Conclusions

This study confirmed that the most downregulated microRNA, miR-33a-5p, can mediate the cisplatin resistance of HCC cells, providing a new and feasible direction for research into combatting liver cancer chemotherapy resistance.

Oxidized Phospholipid OxPAPC Activates TRPA1 and Contributes to Chronic Inflammatory Pain in Mice

Oxidation products of the naturally occurring phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycerol-3-phosphatidylcholine (PAPC), which are known as OxPAPC, accumulate in atherosclerotic lesions and at other sites of inflammation in conditions such as septic inflammation and acute lung injury to exert pro- or anti-inflammatory effects. It is currently unknown whether OxPAPC also contributes to inflammatory pain and peripheral neuronal excitability in these conditions. Here, we observed that OxPAPC dose-dependently and selectively activated human TRPA1 nociceptive ion channels expressed in HEK293 cells in vitro, without any effect on other TRP channels, including TRPV1, TRPV4 and TRPM8. OxPAPC agonist activity was dependent on essential cysteine and lysine residues within the N-terminus of the TRPA1 channel protein. OxPAPC activated calcium influx into a subset of mouse sensory neurons which were also sensitive to the TRPA1 agonist mustard oil. Neuronal OxPAPC responses were largely abolished in neurons isolated from TRPA1-deficient mice. Intraplantar injection of OxPAPC into the mouse hind paw induced acute pain and persistent mechanical hyperalgesia and this effect was attenuated by the TRPA1 inhibitor, HC-030031. More importantly, we found levels of OxPAPC to be significantly increased in inflamed tissue in a mouse model of chronic inflammatory pain, identified by the binding of an OxPAPC-specific antibody. These findings suggest that TRPA1 is a molecular target for OxPAPC and OxPAPC may contribute to chronic inflammatory pain through TRPA1 activation. Targeting against OxPAPC and TRPA1 signaling pathway may be promising in inflammatory pain treatment.

Hepatic carcinoma-associated fibroblasts induce IDO-producing regulatory dendritic cells through IL-6-mediated STAT3 activation

Although carcinoma-associated fibroblasts (CAFs) in tumor microenvironments have a critical role in immune cell modulation, their effects on the generation of regulatory dendritic cells (DCs) are still unclear. In this study, we initially show that CAFs derived from hepatocellular carcinoma (HCC) tumors facilitate the generation of regulatory DCs, which are characterized by low expression of costimulatory molecules, high suppressive cytokines production and enhanced regulation of immune responses, including T-cell proliferation impairment and promotion of regulatory T-cell (Treg) expansion via indoleamine 2,3-dioxygenase (IDO) upregulation. Our findings also indicate that STAT3 activation in DCs, as mediated by CAF-derived interleukin (IL)-6, is essential to IDO production. Moreover, IDO inhibitor, STAT3 and IL-6 blocking antibodies can reverse this hepatic CAF-DC regulatory function. Therefore, our results provide new insights into the mechanisms by which CAFs induce tumor immune escape as well as a novel cancer immunotherapeutic approach (for example, targeting CAFs, IDO or IL-6).

MicroRNA-34a-5p enhances sensitivity to chemotherapy by targeting AXL in hepatocellular carcinoma MHCC-97L cells

Mature microRNA (miRNA) 34a-5p, which is a well-known tumor suppressor in hepatitis virus-associated hepatocellular carcinoma (HCC), plays an important role in cell processes, such as cell proliferation and apoptosis, and is therefore an optimal biomarker for future clinical use. However, the role of miRNA-34a-5p in chemoresistance has yet to be identified. In the present study, the expression of miRNA-34a-5p was assessed by an in situ hybridization assay in HCC tissues and was found to be significantly decreased compared with the pericarcinomatous areas of the tissue specimens, which consisted of samples obtained from 114 patients with HCC. High expression of miRNA-34a-5p was found to be associated with a favorable overall survival time in HCC patients. Functional tests performed by transfecting miRNA-34a-5p mimics or inhibitors into MHCC-97L cells illustrated that miRNA-34a-5p inhibited proliferation, elevated apoptosis and decreased chemoresistance to cisplatin in HCC cells. AXL is the direct target of miRNA-34a-5p, as confirmed by sequence analysis and luciferase assay. Transfection of the cells with small interfering RNA for AXL (siAXL) increased the apoptosis ratio of the MHCC-97L cell line. Transfection with siAXL led to similar biological behaviors in the MHCC-97L cells to those induced by ectopic expression of miRNA-34a-5p. Thus, it was concluded that miRNA-34a-5p enhanced the sensitivity of the cells to chemotherapy by targeting AXL in hepatocellular carcinoma. In addition, low expression of miRNA-34a-5p in HCC tissues yielded an unfavorable prognosis for patients with HCC that received radical surgery, due to the promotion of proliferation and an increase in chemoresistance in HCC cells.

Umbilical cord-derived mesenchymal stem cells instruct dendritic cells to acquire tolerogenic phenotypes through the IL-6-mediated upregulation of SOCS1

The mechanisms responsible for the inhibitory effects of mesenchymal stem cells (MSCs) on dendritic cells (DCs) are still poorly understood. Our investigation of the potential signaling pathways revealed for the first time that human umbilical-cord-derived MSCs (UC-MSCs) instruct DCs to acquire tolerogenic phenotypes through the IL-6-mediated upregulation of SOCS1. This subset of MSC-DCs exhibited a tolerogenic pattern, with a clear decrease in the expression of co-stimulatory molecules and the capacity to stimulate CD3(+) T cell proliferation and inflammatory factor secretion, and a significant increase in the production of inhibitory cytokine IL-10 and the ability to induce Treg cells and Th2 responses. Adoption of this tolerogenic pattern required the activation of SOCS1, which blocked DC maturation by impairing TLR4 signaling. The effects of UC-MSCs on SOCS1 activation were essentially mediated by the JAK-STAT pathway via IL-6 secretion. In summary, our data identify a new mechanism, involving the IL-6-mediated upregulation of SOCS1, by which UC-MSCs instruct DCs to acquire tolerogenic phenotypes.

MiR-124 protects human hepatic L02 cells from H2O2-induced apoptosis by targeting Rab38 gene

BACKGROUND

Hepatic ischemia reperfusion injury (IRI) is an inevitable clinical problem for liver surgeons. Because microRNAs (miRNAs) participate in various hepatic pathophysiological processes, this study aimed to explore the role and potential mechanism of miR-124 in hepatic IRI.

METHODS

A liver IRI model was established in rats. The differential expression of miRNAs was detected using microarrays, and the expression of miR-124 was measured by qRT-PCR. A hydrogen peroxide (H2O2)-induced oxidative stress apoptosis model was also established. Cell apoptosis was detected by flow cytometry, and viability was detected by CCK8. The expression of Rab38 was detected by Western blotting and qRT-PCR, and a luciferase reporter assay was used to verify the expression of the miR-124 target gene.

RESULTS

The miRNA spectrum changes dramatically after hepatic IRI in rats, and miR-124 is significantly down-regulated after liver IRI. MiR-124 decreases the H2O2-induced apoptosis of human hepatic L02 cells by up-regulating the activation of the AKT pathway. Rab38 is a target gene of miR-124 and is involved in H2O2-induced apoptosis. Interference with the expression of the Rab38 gene can protect hepatic L02 from H2O2-induced apoptosis by increasing the phosphorylation of AKT. These protective effects of miR-124 are attenuated by over-expression of Rab38.

CONCLUSIONS

Many miRNAs are involved in hepatic IRI in rats, and miR-124 is significantly decreased in this model. MiR-124 significantly decreases the H2O2-induced apoptosis of human hepatic L02 cells by targeting the Rab38 gene and activating the AKT pathway.

Cancer-associated fibroblasts from hepatocellular carcinoma promote malignant cell proliferation by HGF secretion

Cancer-associated fibroblasts (CAFs) are reported to support tumorigenesis by stimulating angiogenesis, cancer cell proliferation, and invasion in most solid tumors. However, the roles of CAFs in the liver cancer microenvironment have not been thoroughly studied. In our previous study, we successfully isolated CAFs from hepatocellular carcinoma (HCC) (H-CAFs) and proved that H-CAFs suppressed the activation of NK cells and thereby created favorable conditions for HCC progression. In our present study, we found that the proliferation of MHCC97L and Hep3B cells was significantly promoted by treatment with conditioned medium from H-CAFs. Pathological analysis also revealed that H-CAFs increased the proportion of Ki-67 (+) malignant cells and prevented them from undergoing necrosis. Moreover, the concentration of hepatocyte growth factor (HGF) cytokine in the conditioned medium of H-CAFs was higher than conditioned medium from normal skin fibroblasts (NSFs). Anti-HGF significantly reduced the proliferation-promoting capability of H-CAFs. In addition, we found that the abundance of H-CAFs correlated positively with tumor size. These results indicate that H-CAFs are an important factor for promoting the growth of HCC in vitro and in vivo, and that HGF plays a key role in HCC proliferation induced by H-CAFs.

10-Hydroxy-2-decenoic acid prevents ultraviolet A-induced damage and matrix metalloproteinases expression in human dermal fibroblasts

BACKGROUND

10-Hydroxy-2-decenoic acid (10-HDA) is a major fatty acid component of royal jelly, which has been reported to have a variety of beneficial pharmacological characteristics. However, the effects of 10-HDA on skin photoageing and its potential mechanism of action are unclear.

OBJECTIVE

We investigated the protective effects of 10-HDA on ultraviolet (UV) A-induced damage in human dermal fibroblasts (HDFs). We then explored the inhibitory effects of 10-HDA on UVA-induced matrix metalloproteinases (MMPs) expression and elucidated the signalling pathways controlling MMPs inhibition.

METHODS

Primary human dermal fibroblasts were exposed to UVA. Cell proliferation, cellular senescent state and collagen content were analysed using CCK-8, senescence-associated β-galactosidase staining and Sircol collagen assay, respectively. Fluorometric assays were performed to detect the formation of reactive oxygen species (ROS) in the cells. The mRNA levels of MMP-1, MMP-3 and type I (α1) collagen were determined by quantitative real-time PCR. Western blot was applied to detect the expression of MMP-1, MMP-3, JNK and p38 MAPK.

RESULTS

HDFs treated with 10-HDA were significantly protected from UVA-induced cytotoxicity, ROS, cellular senescence and stimulated collagen production. Moreover, 10-HDA suppressed the UVA-induced expression of MMP-1 and MMP-3 at both the transcriptional and protein levels. Treatment with 10-HDA also reduced the UVA-induced activation of the JNK and p38 MAPK pathways.

CONCLUSION

The data obtained in this study provide evidence that 10-HDA could prevent UVA-induced damage and inhibit MMP-1 and MMP-3 expressions. Therefore, 10-HDA may be a potential agent for the prevention and treatment of skin photoageing.

Integrated flexible ocular coil for power and data transfer in retinal prostheses

A microfabricated and fully-implantable coil for use as a power and data transfer component for retinal prostheses is presented. Compared with traditional hand-made ocular coils, this parylene-based device is thin and flexible with 10 turns of thin-film metal wires and a thickness of less than 10 μm. In addition, the entire coil structure can be heat-formed on a mold to match the eye's curvature for extraocular implantation. Because it is made using parylene thin-film technology, this coil can be directly integrated with multielectrode arrays and with parylene-based packages incorporating application specific integrated circuits (ASICs) or discrete electrical components such as chip capacitors. This coil thus enables the fabrication and implantation of a fully microfabricated system for retinal prostheses.

Hepatocellular carcinoma-associated fibroblasts trigger NK cell dysfunction via PGE2 and IDO

Defects in natural killer (NK) cell function are necessary for tumor immune escape, but the underlying regulatory mechanisms in human cancers remain largely unknown. Here we show that fibroblasts derived from hepatocellular carcinoma (HCC) were significantly superior to foreskin-derived fibroblasts at inducing NK cell dysfunction, which is characterized by low expression of cytotoxic molecules and surface markers for cell activation, impaired production of cytokines, and decreased cytotoxicity against K562 cells in vitro. Our results also indicate that PGE2 and IDO, derived from activated fibroblasts, suppress the activation of NK cells and thereby create favorable conditions for tumor progression.

Bone marrow mesenchymal stem cells ameliorate hepatic ischemia/reperfusion injuries via inactivation of the MEK/ERK signaling pathway in rats

BACKGROUND

Primary graft dysfunction or nonfunction after liver transplantation, which is usually caused by ischemia/reperfusion injury (IRI), is a serious clinical problem. Although bone marrow mesenchymal stem cells (MSCs) have shown great potential in cell therapy for IRI in several organs, the mechanism(s) by which MSCs offer protection is unclear.

METHODS

In the present study, we injected MSCs systemically via the tail vein in the rat model of 70% hepatic IRI and measured the biochemical and pathologic alterations to evaluate the therapeutic effect of MSC transplantation. Concurrently, H(2)O(2) was used in vitro to mimic oxidative injury and to induce apoptosis in the human normal liver cell line LO2 to evaluate the protective effects of mesenchymal stem cell conditioned medium (MSC-CM) on LO2 cells.

RESULTS

The systemic infusion of MSCs led to a significant prevention of liver enzyme release and an improvement in the histology of the acutely injured liver. In vitro assays demonstrated that MSC-CM promoted hepatocyte proliferation and had a direct inhibitory effect on hepatocyte apoptosis induced by H(2)O(2). In addition, we demonstrated that the prevention of MEK/ERK pathway activation played a pivotal role in the protection.

CONCLUSIONS

These data suggest that MSC may represent a potential therapeutic strategy to alleviate hepatic ischemia/reperfusion injuries after liver transplantation via inactivation of the MEK/ERK signaling pathway.

Hepatocellular carcinoma-associated fibroblasts trigger NK cell dysfunction via PGE2 and IDO

Defects in natural killer (NK) cell function are necessary for tumor immune escape, but the underlying regulatory mechanisms in human cancers remain largely unknown. Here we show that fibroblasts derived from hepatocellular carcinoma (HCC) were significantly superior to foreskin-derived fibroblasts at inducing NK cell dysfunction, which is characterized by low expression of cytotoxic molecules and surface markers for cell activation, impaired production of cytokines, and decreased cytotoxicity against K562 cells in vitro. Our results also indicate that PGE2 and IDO, derived from activated fibroblasts, suppress the activation of NK cells and thereby create favorable conditions for tumor progression.