GPR39 Overexpression in OSCC Promotes YAP-Sustained Malignant Progression

Targeting of G protein-coupled receptor 39 alleviates angiotensin II-induced renal damage by reducing ribonucleotide reductase M2

Renal fibrosis, apoptosis and autophagy are the main pathological manifestations of angiotensin II (Ang II)-induced renal injury. G protein-coupled receptor 39 (GPR39) is highly expressed in various tissues including the kidney, but its role in the kidney is entirely unclear. This study was performed to investigate the underlying mechanism by which knockdown of GPR39 alleviated Ang II-induced renal injury. In vivo, GPR39 knockout (KO) mice were constructed and infused with Ang II for 4 weeks, followed by renal function tests. In vitro, Ang II-induced cells were treated with si-GPR39 for 48 h. Fibrosis, apoptosis and autophagy were detected in both cells and mice. The underlying mechanism was sought by mRNA transcriptome sequencing and validated in vitro. GPR39 was upregulated in renal tissues of mice with Ang II-mediated renal injury. Knockdown of GPR39 ameliorated renal fibrosis, apoptosis, and autophagy, and decreased the expression of ribonucleotide reductase M2 (RRM2). In vitro, knockdown of GPR39 was also identified to improve the Ang II-induced cell fibrosis, apoptosis, and autophagy. mRNA transcriptome results showed that knockout of GPR39 reduced the expression of RRM2 in Ang II-induced kidney tissue. Activation of RRM2 could reverse the therapeutic effect of GPR39 knockout, and the inhibitor of RRM2 could improve the cell fibrosis, apoptosis and autophagy caused by GPR39 agonist. These results indicated that targeting of GPR39 could alleviate Ang II-induced renal fibrosis, apoptosis, and autophagy via reduction of RRM2 expression, and GPR39 may serve as a potential target for Ang II-induced renal injury.

METTL3 Promotes OSCC Progression by Down-Regulating WEE1 in a m6A-YTHDF2-Dependent Manner

Oral squamous cell carcinoma (OSCC) is a common and highly lethal epithelial cancer. This study aimed to confirm the role of METTL3 in promoting OSCC and investigate its specific underlying mechanisms. Expression of the METTL3, YTH domain-containing family 2 (YTHDF2), and WEE1 were examined in normal oral epithelial cells and OSCC cells. Cell functions were examined after overexpressing WEE1 in OSCC cells. MeRIP-qPCR analysis was used to detect WEE1 m6A levels in HOK, SCC25, and CAL27 cells. WEE1 and its m6A levels were evaluated in OSCC cells by knocking down METTL3/YTHDF2, assessing the interaction between METTL3/YTHDF2 and WEE1. The impact of METTL3 and YTHDF2 downregulation on WEE1 mRNA stability was also investigated. The tumor weight and volume in a nude mouse model of OSCC after overexpression of WEE1 and YTHDF2 were measured. Expression of Ki-67 and WEE1 in OSCC tissue was detected using immunohistochemistry. Compared to normal oral epithelial cells, METTL3 and YTHDF2 were upregulated in OSCC cells, while WEE1 was downregulated, and there was a negative correlation between WEE1 and METTL3/YTHDF2 expression. WEE1 overexpression inhibited proliferation, invasion, and migration while promoting apoptosis in OSCC cells. METTL3 and YTHDF2 bound to WEE1 mRNA. METTL3/YTHDF2 knockdown increased WEE1 levels and WEE1 mRNA stability. METTL3 inhibition reduced WEE1 m6A levels. Inhibition of METTL3 weakened the interaction between YTHDF2 and WEE1 mRNA. In vivo, overexpression of WEE1 suppressed OSCC development, which was reversed by overexpression of YTHDF2. METTL3 facilitates the progression of OSCC through m6A-YTHDF2-dependent downregulation of WEE1.

Natural compounds targeting YAP/TAZ axis in cancer: Current state of art and challenges

Cancer has become a burgeoning global healthcare concern marked by its exponential growth and significant economic ramifications. Though advancements in the treatment modalities have increased the overall survival and quality of life, there are no definite treatments for the advanced stages of this malady. Hence, understanding the diseases etiologies and the underlying molecular complexities, will usher in the development of innovative therapeutics. Recently, YAP/TAZ transcriptional regulation has been of immense interest due to their role in development, tissue homeostasis and oncogenic transformations. YAP/TAZ axis functions as coactivators within the Hippo signaling cascade, exerting pivotal influence on processes such as proliferation, regeneration, development, and tissue renewal. In cancer, YAP is overexpressed in multiple tumor types and is associated with cancer stem cell attributes, chemoresistance, and metastasis. Activation of YAP/TAZ mirrors the cellular "social" behavior, encompassing factors such as cell adhesion and the mechanical signals transmitted to the cell from tissue structure and the surrounding extracellular matrix. Therefore, it presents a significant vulnerability in the clogs of tumors that could provide a wide window of therapeutic effectiveness. Natural compounds have been utilized extensively as successful interventions in the management of diverse chronic illnesses, including cancer. Owing to their capacity to influence multiple genes and pathways, natural compounds exhibit significant potential either as adjuvant therapy or in combination with conventional treatment options. In this review, we delineate the signaling nexus of YAP/TAZ axis, and present natural compounds as an alternate strategy to target cancer.

GPR39: An orphan receptor begging for ligands

Progress in the understanding of the receptor GPR39 is held up by inconsistent pharmacological data. First, the endogenous ligand(s) remain(s) contentious. Data pointing to zinc ions (Zn2+) and/or eicosanoids as endogenous ligands are a matter of debate. Second, there are uncertainties in the specificity of the widely used synthetic ligand (agonist) TC-G 1008. Third, activation of GPR39 has been often proposed as a novel treatment strategy, but new data also support that inhibition might be beneficial in certain disease contexts. Constitutive activity/promiscuous signaling suggests the need for antagonists/inverse agonists in addition to (biased) agonists. Here, we scrutinize data on the signaling and functions of GPR39 and critically assess factors that might have contributed to divergent outcomes and interpretations of investigations on this important receptor.

Does YAP influence cell proliferation and apoptosis in benign epithelial odontogenic lesions?

OBJECTIVE

To analyze the immunohistochemical expression of YAP and its correlation with markers involved in cell proliferation and apoptosis in benign epithelial odontogenic lesions.

STUDY DESIGN

The sample consisted of 95 cases of odontogenic lesions (25 dentigerous cysts, 30 non-syndromic odontogenic keratocysts, 30 conventional ameloblastomas, and 10 unicystic ameloblastomas) and 10 dental follicles used as normal odontogenic tissue. The histological sections were submitted to immunohistochemistry with YAP, cyclin D1, Ki-67, and Bcl-2 antibodies. Immunoexpression was analyzed qualitatively and quantitatively using an adapted method. The collected data were analyzed descriptively and statistically (p ≤ 0.05).

RESULTS

The highest YAP expression was observed in odontogenic keratocysts, followed by unicystic ameloblastomas and conventional ameloblastomas, which exhibited moderate immunoreactivity predominantly in peripheral cells. Furthermore, significant differences in YAP immunoexpression were observed between the groups analyzed, with significant positive correlations between YAP and cyclin D1 in dentigerous cysts and unicystic ameloblastomas and between YAP and Ki-67 in unicystic ameloblastomas (p < 0.05). However, there were no statistically significant correlations between YAP and Bcl-2 immunoexpression in the groups studied.

CONCLUSION

YAP may influence epithelial cell proliferation in odontogenic cysts and tumors, suggesting its possible participation in the progression of the odontogenic lesions studied.

Activation of G protein-coupled receptor 39 alleviates neuropathic pain and chronic inflammation

Neuropathic pain (NP) is mainly caused by lesions or diseases of the somatosensory nervous system and triggers severe physical burdens to patients. It is claimed that activated microglia-mediated neuroinflammation participates in the development of NP, which is regulated by p38 mitogen-activated protein kinase (MAPK)/nuclear factor-κappa B (NF-κB) p65 signaling. G protein-coupled receptor 39 (GPR39) is a trans-membrane protein involved in the activation of cellular transduction pathways, and TC-G 1008, a GPR39 agonist, is believed to have inhibitory effects on neuroinflammation. Our study will explore the possible alleviatory function of TC-G 1008 on NP in a rat model. GPR39 was found markedly downregulated in the spinal dorsal horn of chronic constriction injury (CCI)-stimulated rats. Rats were treated with CCI, followed by intranasal administration with 7.5 and 15 mg/kg TC-G 1008 at 1, 25, 49, and 73 h postmodeling, respectively. Drastically lowered values of paw withdrawal threshold and paw withdrawal latency, upregulated ionized calcium-binding adapter molecule 1, increased release of inflammatory cytokines, elevated spinal malondialdehyde levels, and reduced spinal glutathione peroxidase levels were observed in CCI-stimulated rats, all of which were markedly alleviated and rescued by TC-G 1008. Furthermore, the levels of p-p38/p38 and p-NF-κB p65 were found signally repressed in the spinal dorsal horn of CCI-stimulated rats, which was notably reversed by TC-G 1008. Collectively, TC-G 1008 markedly alleviated NP and neuroinflammation in CCI-treated rats. Our findings provide an attractive future direction for the treatment of NP.

NFE2L1 restrains ferroptosis by transcriptionally regulating HJURP and participates in the progress of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common head and neck malignancy with increasing mortality and high recurrence. In this work, we aim to explore the functional role of NFE2 like bZIP transcription factor 1 (NFE2L1) in OSCC progression. Based on databases analysis, we found that NFE2L1 was overexpressed in OSCC tumor tissues, and elevated NFE2L1 level induced poor prognosis of OSCC patients. Our results showed that NFE2L1 is upregulated in OSCC cells and overexpression of NFE2L1 promotes cell proliferation, and reduces the sensitivity of OSCC cells to erastin-induced ferroptosis. NFE2L1 upregulation decreased the levels of Fe2+, lipid reactive oxygen species and content of malondialdehyde, and increased the level of the key negative regulator of ferroptosis, GPX4 and SLC7A11. In NFE2L1 suppressed cells, these trends were reversed. Further results of dual luciferase reporter and chromatin immunoprecipitation assays confirmed that NFE2L1 could bind to the promoter of Holliday junction recognition protein (HJURP) to increase the transcriptional activity of HJURP, thus upregulating its expression. Inhibition of HJURP attenuated the proliferation and ferroptosis inhibition in NFE2L1 upregulated cells. In vivo tumorigenicity assay further proved that NFE2L1 promotes OSCC tumor growth. In summary, NFE2L1 restrains ferroptosis by transcriptionally regulating HJURP and participates in the progress of OSCC. Thus, NFE2L1 plays a key role in OSCC development and may be a promising therapeutic target for OSCC.

A four-gene-based methylation signature associated with lymph node metastasis predicts overall survival in lung squamous cell carcinoma

We aimed to identify prognostic methylation genes associated with lymph node metastasis (LNM) in lung squamous cell carcinoma (LUSC). Bioinformatics methods were used to obtain optimal prognostic genes for risk model construction using data from the Cancer Genome Atlas database. ROC curves were adopted to predict the prognostic value of the risk model. Multivariate regression was carried out to identify independent prognostic factors and construct a prognostic nomogram. The differences in overall survival, gene mutation and pathways between high- and low-risk groups were analyzed. Finally, the expression and methylation level of the optimal prognostic genes among different LNM stages were analyzed. FGA, GPR39, RRAD and TINAGL1 were identified as the optimal prognostic genes and were applied to establish a prognostic risk model. Significant differences were found among the different LNM stages. The risk model could predict overall survival, showing a moderate performance with AUC of 0.64-0.68. The model possessed independent prognostic value, and could accurately predict 1-, 3- and 5-year survival. Patients with a high risk score showed poorer survival. Lower gene mutation frequencies and enrichment of leukocyte transendothelial migration and the VEGF signaling pathway in the high-risk group may lead to the poor prognosis. This study identified several specific methylation markers associated with LNM in LUSC and generated a prognostic model to predict overall survival for LUSC patients.

miR-19a may function as a biomarker of oral squamous cell carcinoma (OSCC) by regulating the signaling pathway of miR-19a/GRK6/GPCRs/PKC in a Chinese population

BACKGROUND

In this study, we aimed to investigate the potential of miR-19a as a biomarker of OSCC and its underlying molecular mechanisms.

METHODS

We collected serum and saliva samples from 66 OSCC patients and 66 healthy control subjects. Real-time PCR analysis, bioinformatic analysis and luciferase assays were performed to establish a potential signaling pathway of miR-19a/GRK6/GPCRs/PKC. Flowcytometry and Transwell assays were performed to observe the changes in cell apoptosis, metastasis and invasion.

RESULTS

We found that miR-19a, GPR39 mRNA and PKC mRNA were upregulated while GRK6 mRNA was downregulated in the serum and saliva samples collected from OSCC patients. Moreover, in silico analysis confirmed a potential binding site of miR-19a on the 3'UTR of GRK6 mRNA, and the subsequent luciferase assays confirmed the molecular binding between GRK6 and miR-19a. We further identified that the over-expression of miR-19a could regulate the signaling between GRK6, GPR39 and PKC via the signaling pathway of miR-19a/GRK6/GPR39/PKC, which accordingly resulted in suppressed cell apoptosis and promoted cell migration and invasion.

CONCLUSION

Collectively, the findings of our study propose that miR-19a is a crucial mediator in the advancement of OSCC, offering a potential avenue for the development of innovative therapeutic interventions aimed at regulating GRK6 and its downstream signaling pathways.

Prognostic Value of Necroptosis-Related Genes Signature in Oral Squamous Cell Carcinoma

The dual role of necroptosis in inhibiting and promoting tumor development has gradually received much attention because of its essential significance for targeted treatment. Accordingly, this study aims to explore the relationship between necroptosis and oral squamous cell carcinoma (OSCC), and search for novel prognostic factors for OSCC. RNA-seq data and clinical information were downloaded from TCGA and GTEx databases. The prognostic signature of necroptosis-related genes (NRGs) was constructed by univariate Cox regression analysis and the LASSO Cox regression model. Moreover, survival analyses, ROC curves, and nomograms were adopted to further analyze. GO and KEGG analyses and immune infiltration analyses were used for function enrichment and immune feature research in turn. The NRG prognostic signature expression was higher in OSCC tissues than in normal tissues, and the overall survival (OS) rate of the high-expression group was much lower. HPRT1 was proved to be an independent prognostic factor in OSCC. Furthermore, the function enrichment analyses revealed that NRGs were involved in necroptosis, apoptosis, inflammation, and immune reaction. The expression of NRGs was related to immunosuppression in OSCC. Furthermore, the knockdown of HPRT1 could suppress the proliferation and migration of OSCC. In conclusion, the high expression of NRG prognostic signature is associated with poor prognosis in OSCC, and HPRT1 can serve as a novel independent prognostic factor for OSCC.

Overexpression of RAB27A in Oral Squamous Cell Carcinoma Promotes Tumor Migration and Invasion via Modulation of EGFR Membrane Stability

Oral squamous cell carcinoma (OSCC) is the most prevalent subtype of head and neck tumors, highly prone to lymph node metastasis. This study aims to examine the expression pattern of Ras-related protein Rab-27A (RAB27A) and explore its potential implications in OSCC. The expression of RAB27A was assessed through immunohistochemical analysis utilizing tissue microarrays. In vitro experiments were conducted using RAB27A-knockdown cells to investigate its impact on OSCC tumor cells. Additionally, transcriptome sequencing was performed to elucidate potential underlying mechanisms. RAB27A was significantly overexpressed in OSCC, and particularly in metastatic lymph nodes. It was positively correlated with the clinical progression and poor survival prognosis. Silencing RAB27A notably decreased the proliferation, migration, and invasion abilities of OSCC cells in vitro. A Gene Ontology (GO) enrichment analysis indicated a strong association between RAB27A and the epidermal growth factor receptor (EGFR) signaling pathway. Further investigations revealed that RAB27A regulated the palmitoylation of EGFR via zinc finger DHHC-type containing 13 (ZDHHC13). These findings provide insights into OSCC progression and highlight RAB27A as a potential therapeutic target for combating this aggressive cancer.

YAP/TAZ: Molecular pathway and disease therapy

The Yes-associated protein and its transcriptional coactivator with PDZ-binding motif (YAP/TAZ) are two homologous transcriptional coactivators that lie at the center of a key regulatory network of Hippo, Wnt, GPCR, estrogen, mechanical, and metabolism signaling. YAP/TAZ influences the expressions of downstream genes and proteins as well as enzyme activity in metabolic cycles, cell proliferation, inflammatory factor expression, and the transdifferentiation of fibroblasts into myofibroblasts. YAP/TAZ can also be regulated through epigenetic regulation and posttranslational modifications. Consequently, the regulatory function of these mechanisms implicates YAP/TAZ in the pathogenesis of metabolism-related diseases, atherosclerosis, fibrosis, and the delicate equilibrium between cancer progression and organ regeneration. As such, there arises a pressing need for thorough investigation of YAP/TAZ in clinical settings. In this paper, we aim to elucidate the signaling pathways that regulate YAP/TAZ and explore the mechanisms of YAP/TAZ-induce diseases and their potential therapeutic interventions. Furthermore, we summarize the current clinical studies investigating treatments targeting YAP/TAZ. We also address the limitations of existing research on YAP/TAZ and propose future directions for research. In conclusion, this review aims to provide fresh insights into the signaling mediated by YAP/TAZ and identify potential therapeutic targets to present innovative solutions to overcome the challenges associated with YAP/TAZ.

Signaling pathway mechanisms of neurological diseases induced by G protein-coupled receptor 39

BACKGROUND

G protein-coupled receptor 39 (GPR39) is a transmembrane zinc receptor with two splice variants, which belongs to the G-protein-coupled receptor growth hormone-releasing peptide family. Its expression is induced by zinc, which activates GPR39, and its activation mediates cell proliferation, ion homeostasis, and anti-inflammatory, antioxidant, and other pathophysiological effects via different signaling pathways.

AIMS

The article reviews the latest literature in this field. In particular, the role of GPR39 in nervous system is discussed.

MATERIALS AND METHODS

GPR39 can be a promising target in neurological diseases for targeted therapy, which will help doctors overcome the associated problems.

DISCUSSION

GPR39 is expressed in vivo at several sites. Increasing evidence suggests that GPR39 plays an important role as a neuroprotective agent in vivo and regulates various neurological functions, including neurodegeneration, neuroelectrophysiology, and neurovascular homeostasis.

CONCLUSION

This review aims to provide an overview of the functions, signal transduction pathways, and pathophysiological role of GPR39 in neurological diseases and summarize the GPR39 agonists that have been identified in the recent years.

Novel Double-Layer Dissolving Microneedles for Transmucosal Sequential Delivery of Multiple Drugs in the Treatment of Oral Mucosa Diseases

The development of transmucosal drug delivery systems is a practical requirement in oral clinical practice, and controlled sequential delivery of multiple drugs is usually required. On the basis of the previous successful construction of monolayer microneedles (MNs) for transmucosal drug delivery, we designed transmucosal double-layer sequential dissolving MNs using hyaluronic acid methacryloyl (HAMA), hyaluronic acid (HA), and polyvinyl pyrrolidone (PVP). MNs have the advantages of small size, easy operation, good strength, rapid dissolution, and one-time delivery of two drugs. Morphological test results showed that the HAMA-HA-PVP MNs were small and intact in structure. The mechanical strength and mucosal insertion test results indicated the HAMA-HA-PVP MNs had appropriate strength and could penetrate the mucosal cuticle quickly to achieve transmucosal drug delivery. The in vitro and in vivo experiment results of the double-layer fluorescent dyes simulating drug release revealed that MNs had good solubility and achieved stratified release of the model drugs. The results of the in vivo and in vitro biosafety tests also indicated that the HAMA-HA-PVP MNs were biosafe materials. The therapeutic effect of drug-loaded HAMA-HA-PVP MNs in the rat oral mucosal ulcer model demonstrated that these novel HAMA-HA-PVP MNs quickly penetrated the mucosa, dissolved and effectively released the drug, and achieved sequential drug delivery. Compared to monolayer MNs, these HAMA-HA-PVP MNs can be used as double-layer drug reservoirs for controlled release, effectively releasing the drug in the MN stratification by dissolution in the presence of moisture. The need for secondary or multiple injections can be avoided, thus improving patient compliance. This drug delivery system can serve as an efficient, multipermeable, mucosal, and needle-free alternative for biomedical applications.

Tissue mechanics modulate PCNP expression in oral squamous cell carcinomas with different differentiation

Background

PEST-containing nuclear protein (PCNP), a novel zinc finger protein, participates in cell cycle regulation. Previous studies have confirmed that PCNP plays a role in mediating cellular development and invasion in a variety of cancer types. However, the relationship between PCNP expression and the occurrence and development of oral squamous cell carcinoma (OSCC) requires further exploration. In this study, we used biological atomic force microscopy to examine the histomorphological and mechanical properties of OSCC to explore the relationship between PCNP expression and differentiation of OSCC.

Methods

Seventy-seven OSCC samples with varying degrees of differentiation were selected for hematoxylin and eosin staining, immunohistochemistry, and cellular mechanical measurement. The expression of PCNP and the mechanical properties such as stiffness and roughness of the tissue interface in OSCC samples were investigated. The Kaplan-Meier survival curve was utilized to assess the relationship of PCNP expression with patient survival.

Results

The level of PCNP was significantly higher in well-differentiated OSCC than in moderately and poorly differentiated OSCC (P < 0.001). High expression of PCNP was specifically associated with higher tumor differentiation, lack of lymph node metastasis, and lower tumor node metastasis stage (all P < 0.05). Patients with high PCNP expression had a higher survival rate than those with low PCNP expression. The average variation of stiffness within a single tissue ranged from 347 kPa to 539 kPa. The mean surface roughness of highly, moderately, and poorly differentiated OSCC and paraneoplastic tissues were 795.53 ± 47.2 nm, 598.37 ± 45.76 nm, 410.16 ± 38.44 nm, and 1010.94 ± 119.07 nm, respectively. Pearson correlation coefficient demonstrated a positive correlation between PCNP expression and tissue stiffness of OSCC (R = 0.86, P < 0.001).

Conclusion

The expression of PCNP was positively correlated with patient survival, tumor differentiation, and mechanical properties of tissue interfaces. PCNP is a potential biomarker for the early diagnosis and staging of OSCC. Furthermore, determination of the mechanical properties of the tissue interface could provide further useful information required for the detection and differentiation of OSCC.

Cigarette smoking induces the activation of RIP2/caspase-12/NF-κB axis in oral squamous cell carcinoma

Cigarette smoking is one of the major risk factors for the occurrence and progression of oral squamous cell carcinoma (OSCC). Receptor-interacting protein 2 (RIP2) has been involved in mucosal immunity and homeostasis via a positive regulation of nuclear factor κB (NF-κB) transcription factor activity. Caspase-12 can bind to RIP2 and dampen mucosal immunity. However, the roles of RIP2/NF-κB and caspase-12 in OSCC induced by cigarette smoking remain unknown. Herein, we investigated the effects of cigarette smoking on the RIP2/NF-κB and caspase-12 in human OSCC tissues and OSCC cell lines (HSC-3). We first observed that RIP2 mediated NF-κB activation and caspase-12 upregulation in OSCC patients with cigarette smoking and cigarette smoke extract (CSE)-treated HSC-3 cells, respectively. Moreover, we confirmed that the downregulation of RIP2 by siRNA resulted in the reduction of caspase-12 expression and NF-κB activity in the presence of CSE treatment in vitro. In summary, our results indicated that cigarette smoking induced the activation of the RIP2/caspase-12/NF-κB axis and it played an important role in the development of OSCC. The RIP2/caspase-12/NF-κB axis could be a target for OSCC prevention and treatment in the future.

Gq Signaling in Autophagy Control: Between Chemical and Mechanical Cues

All processes in human physiology relies on homeostatic mechanisms which require the activation of specific control circuits to adapt the changes imposed by external stimuli. One of the critical modulators of homeostatic balance is autophagy, a catabolic process that is responsible of the destruction of long-lived proteins and organelles through a lysosome degradative pathway. Identification of the mechanism underlying autophagic flux is considered of great importance as both protective and detrimental functions are linked with deregulated autophagy. At the mechanistic and regulatory levels, autophagy is activated in response to diverse stress conditions (food deprivation, hyperthermia and hypoxia), even a novel perspective highlight the potential role of physical forces in autophagy modulation. To understand the crosstalk between all these controlling mechanisms could give us new clues about the specific contribution of autophagy in a wide range of diseases including vascular disorders, inflammation and cancer. Of note, any homeostatic control critically depends in at least two additional and poorly studied interdependent components: a receptor and its downstream effectors. Addressing the selective receptors involved in autophagy regulation is an open question and represents a new area of research in this field. G-protein coupled receptors (GPCRs) represent one of the largest and druggable targets membrane receptor protein superfamily. By exerting their action through G proteins, GPCRs play fundamental roles in the control of cellular homeostasis. Novel studies have shown Gαq, a subunit of heterotrimeric G proteins, as a core modulator of mTORC1 and autophagy, suggesting a fundamental contribution of Gαq-coupled GPCRs mechanisms in the control of this homeostatic feedback loop. To address how GPCR-G proteins machinery integrates the response to different stresses including oxidative conditions and mechanical stimuli, could provide deeper insight into new signaling pathways and open potential and novel therapeutic strategies in the modulation of different pathological conditions.

Composite dissolvable microneedle patch for therapy of oral mucosal diseases

A composite microneedle patch (MN patch) is developed for oral transmucosal administration. To improve the oral transmucosal drug delivery efficiency, the composite MN patch is designed to consist of an array of 100 dissolvable microneedles (MNs) with drug-loaded tips and a backing layer. The MNs are composed of two parts, the hyaluronic acid (HA) tip part and the polyvinylpyrrolidone (PVP) base part. Due to the small size and sufficient mechanical strength, the HA-PVP MNs can painlessly penetrate the oral mucosa barrier and deliver drugs directly to the basal layer or submucosa. Betamethasone sodium phosphate (BSP), as the model drug, is concentrated in the HA tip parts to avoid the drug waste caused by mucosa elasticity. Considering the special moist environment and saliva flow in the mouth, a double-layer backing layer composed of a poly(vinyl alcohol) (PVA) adhesive layer and an ethyl cellulose (EC) waterproof layer is designed and constructed, which could reduce the saliva flow effects. The in vitro and in vivo results demonstrate that the MN patch could achieve rapid and efficient BSP release in oral mucosa due to the rapid dissolution of HA. The proposed MN patch provides a novel strategy for the therapy of oral mucosal diseases.

Molecular Research on Oral Diseases and Related Biomaterials: A Journey from Oral Cell Models to Advanced Regenerative Perspectives

Oral diseases such as gingivitis, periodontitis, and oral cancer affect millions of people worldwide. Much research has been conducted to understand the pathogenetic mechanisms of these diseases and translate this knowledge into therapeutics. This review aims to take the reader on a journey from the initial molecular discoveries to complex regenerative issues in oral medicine. For this, a semi-systematic literature search was carried out in Medline and Web of Science databases to retrieve the primary literature describing oral cell models and biomaterial applications in oral regenerative medicine. First, an in vitro cell model of gingival keratinocytes is discussed, which illustrates patho- and physiologic principles in the context of oral epithelial homeostasis and carcinogenesis and represents a cellular tool to understand biomaterial-based approaches for periodontal tissue regeneration. Consequently, a layered gradient nonwoven (LGN) is described, which demonstrates that the key features of biomaterials serve as candidates for oral tissue regeneration. LGN supports proper tissue formation and obeys the important principles for molecular mechanotransduction. Furthermore, current biomaterial-based tissue regeneration trends, including polymer modifications, cell-based treatments, antimicrobial peptides and optogenetics, are introduced to represent the full spectrum of current approaches to oral disease mitigation and prevention. Altogether, this review is a foray through established and new concepts in oral regenerative medicine and illustrates the process of knowledge translation from basic molecular and cell biological research to future clinical applications.

Activation of GPR39 with TC-G 1008 attenuates neuroinflammation via SIRT1/PGC-1α/Nrf2 pathway post-neonatal hypoxic-ischemic injury in rats

Background

Hypoxic–ischemic encephalopathy (HIE) is a severe anoxic brain injury that leads to premature mortality or long-term disabilities in infants. Neuroinflammation is a vital contributor to the pathogenic cascade post-HIE and a mediator to secondary neuronal death. As a plasma membrane G-protein-coupled receptor, GPR39, exhibits anti-inflammatory activity in several diseases. This study aimed to explore the neuroprotective function of GPR39 through inhibition of inflammation post-hypoxic–ischemic (HI) injury and to elaborate the contribution of sirtuin 1(SIRT1)/peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α)/nuclear factor, erythroid 2 like 2(Nrf2) in G-protein-coupled receptor 39 (GPR39)-mediated protection.

Methods

A total of 206 10-day-old Sprague Dawley rat pups were subjected to HIE or sham surgery. TC-G 1008 was administered intranasally at 1 h, 25 h, 49 h, and 73 h post-HIE induction. SIRT1 inhibitor EX527, GPR39 CRISPR, and PGC-1α CRISPR were administered to elucidate the underlying mechanisms. Brain infarct area, short-term and long-term neurobehavioral tests, Nissl staining, western blot, and immunofluorescence staining were performed post-HIE.

Results

The expression of GPR39 and pathway-related proteins, SIRT1, PGC-1α and Nrf2 were increased in a time-dependent manner, peaking at 24 h or 48-h post-HIE. Intranasal administration of TC-G 1008 reduced the percent infarcted area and improved short-term and long-term neurological deficits. Moreover, TC-G 1008 treatment significantly increased the expression of SIRT1, PGC-1α and Nrf2, but downregulated the expressions of IL-6, IL-1β, and TNF-α. GPR39 CRISPR EX527 and PGC-1α CRISPR abolished GPR39’s neuroprotective effects post-HIE.

Conclusions

TC-G 1008 attenuated neuroinflammation in part via the SIRT1/PGC-1α/Nrf2 pathway in a neonatal rat model of HIE. TC-G 1008 may be a novel therapeutic target for treatment post-neonatal HIE injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02289-7.

Targeting-YAP/TAZ therapies for head and neck cancer, directly or indirectly?

YAP/TAZ are wild over-activated in head and neck squamous cell carcinoma (HNSCC) with high potential as a direct therapy target for HNSCC treatments. However, the efforts on the directly targeting-YAP/TAZ therapies over the past decade, have very limited impacts, mainly caused by: 1. There is still none effective and specific YAP/TAZ inhibitor with clinical potential; 2. YAP/TAZ might not be directly targeted, because of their multiple important biological functions, such as: regulation of cell proliferation and survival, stem cell maintain, regulation of organ development, organ size control, and tissue regeneration. Interestingly, the over-activation of YAP/TAZ in HNSCC mainly be regulated by upstream abnormal molecular or biological events, instead of genes alteration of YAP/TAZ. Therefore, exploring the alternative molecular events regulating YAP/TAZ activation and molecular mechanism in HNSCC might help to uncover novel indirect targets of YAP/TAZ therapies for HNSCC prevention and treatment.

Stromal cells in the tumor microenvironment promote the progression of oral squamous cell carcinoma

The stromal cells in the tumor microenvironment (TME) can influence the progression of multiple types of cancer; however, data on oral squamous cell carcinoma (OSCC) are limited. In the present study, the effects of verrucous squamous cell carcinoma-associated stromal cells (VSCC-SCs), squamous cell carcinoma-associated stromal cells (SCC-SCs) and human dermal fibroblasts (HDFs) on the tumor nest formation, proliferation, invasion and migration of HSC-3 cells were examined in vitro using Giemsa staining, MTS, and Transwell (invasion and migration) assays, respectively. The results revealed that both the VSCC-SCs and SCC-SCs inhibited the tumor nest formation, and promoted the proliferation, invasion and migration of OSCC cells in vitro. Furthermore, the effects of VSCC-SCs, SCC-SCs and HDFs on the differentiation, proliferation, invasion and migration of OSCC cells in vivo were evaluated by hematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, immunohistochemistry and double-fluorescent immunohistochemical staining, respectively. The results demonstrated that the VSCC-SCs promoted the differentiation, proliferation, invasion and migration of OSCC cells, while the SCC-SCs inhibited the differentiation, and promoted the proliferation, invasion and migration of OSCC cells in vivo. Finally, microarray data were used to predict genes in VSCC-SCs and SCC-SCs that may influence the progression of OSCC, and those with potential to influence the differential effects of VSCC-SCs and SCC-SCs on the differentiation of OSCC. It was found that C-X-C motif chemokine ligand (CXCL)8, mitogen-activated protein kinase 3 (MAPK3), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), C-X-C motif chemokine ligand 1 (CXCL1) and C-C motif chemokine ligand 2 (CCL2) may be involved in the crosstalk between VSCC-SCs, SCC-SCs and OSCC cells, which regulates the progression of OSCC. Intercellular adhesion molecule 1 (ICAM1), interleukin (IL)1B, Fos proto-oncogene, AP-1 transcription factor subunit (FOS), bone morphogenetic protein 4 (BMP4), insulin (INS) and nerve growth factor (NGF) may be responsible for the differential effects of VSCC-SCs and SCC-SCs on the differentiation of OSCC. On the whole, the present study demonstrates that both VSCC-SCs and SCC-SCs may promote the progression of OSCC, and SCC-SCs were found to exert a more prominent promoting effect; this may represent a potential regulatory mechanism for the progression of OSCC.

The Zinc-Sensing Receptor GPR39 in Physiology and as a Pharmacological Target

The G-protein coupled receptor GPR39 is abundantly expressed in various tissues and can be activated by changes in extracellular Zn²⁺ in physiological concentrations. Previously, genetically modified rodent models have been able to shed some light on the physiological functions of GPR39, and more recently the utilization of novel synthetic agonists has led to the unraveling of several new functions in the variety of tissues GPR39 is expressed. Indeed, GPR39 seems to be involved in many important metabolic and endocrine functions, but also to play a part in inflammation, cardiovascular diseases, saliva secretion, bone formation, male fertility, addictive and depression disorders and cancer. These new discoveries offer opportunities for the development of novel therapeutic approaches against many diseases where efficient therapeutics are still lacking. This review focuses on Zn²⁺ as an endogenous ligand as well as on the novel synthetic agonists of GPR39, placing special emphasis on the recently discovered physiological functions and discusses their pharmacological potential.

Orchestration of Intracellular Circuits by G Protein-Coupled Receptor 39 for Hepatitis B Virus Proliferation

Hepatitis B virus (HBV), a highly persistent pathogen causing hepatocellular carcinoma (HCC), takes full advantage of host machinery, presenting therapeutic targets. Here we aimed to identify novel druggable host cellular factors using the reporter HBV we have recently generated. In an RNAi screen of G protein-coupled receptors (GPCRs), GPCR39 (GPR39) appeared as the top hit to facilitate HBV proliferation. Lentiviral overexpression of active GPR39 proteins and an agonist enhanced HBV replication and transcriptional activities of viral promoters, inducing the expression of CCAAT/enhancer binding protein (CEBP)-β (CEBPB). Meanwhile, GPR39 was uncovered to activate the heat shock response, upregulating the expression of proviral heat shock proteins (HSPs). In addition, glioma-associated oncogene homologue signaling, a recently reported target of GPR39, was suggested to inhibit HBV replication and eventually suppress expression of CEBPB and HSPs. Thus, GPR39 provirally governed intracellular circuits simultaneously affecting the carcinopathogenetic gene functions. GPR39 and the regulated signaling networks would serve as antiviral targets, and strategies with selective inhibitors of GPR39 functions can develop host-targeted antiviral therapies preventing HCC.