Leucine-rich glioma inactivated 3 promotes HaCaT keratinocyte migration

Kappaphycus alvarezii as a renewable source of kappa-carrageenan and other cosmetic ingredients

Kappa-carrageenan is one of the most traded marine-derived hydrocolloids used in the food-and-beverage, pharmaceuticals, and personal care/cosmetics industries. K. alvarezii (previously known as Kappaphycus alvarezii) is arguably the most important natural producer based on annual production size and near-homogeneity of the product (i.e., primarily being the kappa-type). The anticipated expansion of the kappa-carrageenan market in the coming years could easily generate >100,000 MT of residual K. alvarezii biomass per year, which, if left untreated, can severely affect the environment and economy of the surrounding area. Among several possible valorization routes, turning the biomass residue into anti-photoaging cosmetic ingredients could potentially be the most sustainable one. Not only optimizing the profit (thus better ensuring economic sustainability) relative to the biofuels- and animal feed-routes, the action could also promote environmental sustainability. It could reduce the dependency of the current cosmetic industry on both petrochemicals and terrestrial plant-derived bioactive compounds. Note how, in contrast to terrestrial agriculture, industrial cultivation of seaweeds does not require arable land, freshwater, fertilizers, and pesticides. The valorization mode could also facilitate the sequestration of more greenhouse gas CO2 as daily-used chemicals, since the aerial productivity of seaweeds is much higher than that of terrestrial plants. This review first summarizes any scientific evidence that K. alvarezii extracts possess anti-photoaging properties. Next, realizing that conventional extraction methods may prevent the use of such extracts in cosmetic formulations, this review discusses the feasibility of obtaining various K. alvarezii compounds using green methods. Lastly, a perspective on several potential challenges to the proposed valorization scheme, as well as the potential solutions, is offered.

Leucine rich repeat LGI family member 3: Integrative analyses support its prognostic association with pancreatic adenocarcinoma

Leucine rich repeat LGI family member 3 (LGI3) is a member of the LGI protein family. Previous studies of our group have reported that LGI3 is expressed in adipose tissue, skin and brain, and serves as a multifunctional cytokine. LGI3 may also be involved in cytokine networks in various cancers. This study aimed to analyze differentially expressed genes in pancreatic adenocarcinoma (PAC) tissues and PAC cohort data in order to evaluate the prognostic role of LGI3. The expression microarray and the PAC cohort data were analyzed by bioinformatic methods for differential expression, protein-protein interactions, functional enrichment and pathway analyses, gene co-expression network analysis, and prognostic association analysis. Results showed that LGI3 expression was significantly reduced in PAC tissues. Nineteen upregulated genes and 31 downregulated genes in PAC tissues were identified as LGI3-regulated genes. Protein-protein interaction network analysis demonstrated that 92% (46/50) of the LGI3-regulated genes that were altered in PACs belonged to a protein-protein interaction network cluster. Functional enrichment and gene co-expression network analyses demonstrated that these genes in the network cluster were associated with various processes including inflammatory and immune responses, metabolic processes, cell differentiation, and angiogenesis. PAC cohort analyses revealed that low expression levels of LGI3 were significantly associated with poor PAC prognosis. Analysis of favorable or unfavorable prognostic gene products in PAC showed that 93 LGI3-regulated genes were differentially associated with PAC prognosis. LGI3 expression was correlated with the tumor-infiltration levels of various immune cells. Taken together, these results suggested that LGI3 may be a potential prognostic marker of PAC.

The Epidermal Keratinocyte as a Therapeutic Target for Management of Diabetic Wounds

Diabetes mellitus (DM) is an important cause of chronic wounds and non-traumatic amputation. The prevalence and number of cases of diabetic mellitus are increasing worldwide. Keratinocytes, the outermost layer of the epidermis, play an important role in wound healing. A high glucose environment may disrupt the physiologic functions of keratinocytes, resulting in prolonged inflammation, impaired proliferation, and the migration of keratinocytes and impaired angiogenesis. This review provides an overview of keratinocyte dysfunctions in a high glucose environment. Effective and safe therapeutic approaches for promoting diabetic wound healing can be developed if molecular mechanisms responsible for keratinocyte dysfunction in high glucose environments are elucidated.

Integrative proteomic network analyses support depot-specific roles for leucine rich repeat LGI family member 3 in adipose tissues

LGI family member 3 (LGI3) is a member of the LGI protein family. In our previous studies, LGI3 was determined to be expressed in adipose tissues, skin and the brain, where it served as a pleiotropic cytokine. The results indicated that LGI3 levels are increased in adipose tissues of obese individuals in comparison with control individuals and that LGI3 suppressed adipogenesis via its receptor, disintegrin and metalloproteinase domain-containing protein 23. Additionally, it was reported that LGI3 upregulates tumor necrosis factor-α and downregulated adiponectin and hypothesized that LGI3 may act as a proinflammatory adipokine involved in adipose tissue inflammation. In the present study, cytokine arrays were used to analyze cytokine levels in adipose tissues and plasma of LGI3-knockout mice and signaling protein arrays used to analyze the expression and phosphorylation of these proteins in LGI3-treated preadipocytes. The results suggested that expression levels of 129 gene products (24 cytokines and 105 signaling proteins) were altered in response to LGI3 deficiency or LGI3 treatment, respectively. Protein-protein interaction network analysis of LGI3-regulated gene products revealed that 94% of the gene products (21 cytokines and 100 signaling proteins) formed an interaction network cluster. Functional enrichment analysis for the LGI3-regulated gene products, including those from our previous studies, revealed an association with numerous biological processes, including inflammatory responses, cellular differentiation and development and metabolic regulation. Gene co-expression network analysis revealed that these LGI3-regulated gene products were involved in various biological processes in an overlapping and differential manner between subcutaneous and visceral adipose tissues. Notably, inflammatory responses were more strongly associated with the LGI3-regulated gene co-expression network in visceral adipose tissues than in subcutaneous adipose tissues. Analysis of expression quantitative trait loci identified four single nucleotide variants that affect expression of LGI3 in an adipose depot-specific manner. Taken together, the results suggested that LGI3 may serve depot-specific roles as an adipokine in adipose tissues.

The Suppressive Effect of Leucine-Rich Glioma Inactivated 3 (LGI3) Peptide on Impaired Skin Barrier Function in a Murine Model Atopic Dermatitis

This study aimed to restore the skin barrier function from atopic dermatitis (AD) via treatment with leucine-rich glioma inactivated 3 (LGI3) peptide. Male NC/Nga mice (7 weeks, 20 g) were randomly allocated into three groups (control, AD, and LGI3 group). After induction of AD skin lesions with Dermatophagoides farinae ointment, mice were treated with LGI3. The clinical score of AD was the highest and the dorsal skin thickness was the thickest in the AD group. In contrast, LGI3 treatment improved the clinical score and the dorsal skin thickness compared to the AD model. LGI3 treatment suppressed histopathological thickness of the epithelial cell layer of the dorsal skin. LGI3 treatment could indirectly reduce mast cell infiltration through restoring the barrier function of the skin. Additionally, the filaggrin expression was increased in immunohistochemical evaluation. In conclusion, the ameliorating effect and maintaining skin barrier homeostasis in the AD murine model treated with LGI3 could be attributed to complete re-epithelialization of keratinocytes. Hence, LGI3 might be considered as a new potential therapeutic target for restoring skin barrier function in AD.

PTH Derivative promotes wound healing via synergistic multicellular stimulating and exosomal activities

BACKGROUND

Diabetic wounds are a disturbing and rapidly growing clinical problem. A novel peptide, parathyroid hormone related peptide (PTHrP-2), is assumed as multifunctional factor in angiogenesis, fibrogenesis and re-epithelization. This study aims to test PTHrP-2 efficiency and mechanism in wound healing.

METHODS

Through repair phenomenon in vivo some problems were detected, and further research on their mechanisms was made. In vivo therapeutic effects of PTHrP-2 were determined by HE, Masson, microfil and immunohistochemical staining. In vitro direct effects of PTHrP-2 were determined by proliferation, migration, Vascular Endothelial Grown Factor and collagen I secretion of cells and Akt/ Erk1/2 pathway change. In vitro indirect effects of PTHrP-2 was study via exosomes. Exosomes from PTHrP-2 untreated and treated HUVECs and HFF-1 cells were insolated and identified. Exosomes were co-cultured with original cells, HUVECs or HFF-1 cells, and epithelial cells. Proliferation and migration and pathway change were observed. PTHrP-2-HUVEC-Exos were added into in vivo wound to testify its hub role in PTHrP-2 indirect effects in wound healing.

RESULTS

In vivo, PTHrP-2 exerted multifunctional pro-angiogenesis, pro-firbogenesis and re-epithelization effects. In vitro, PTHrP-2 promoted proliferation and migration of endothelial and fibroblast cells, but had no effect on epithelial cells. Therefore, we tested PTHrP-2 indirect effects via exosomes. PTHrP-2 intensified intercellular communication between endothelial cells and fibroblasts and initiated endothelial-epithelial intercellular communication. PTHrP-2-HUVEC-Exos played a hub role in PTHrP-2 indirect effects in wound healing.

CONCLUSION

These findings of this study indicated that PTHrP-2, a multifunctional factor, could promote wound healing via synergistic multicellular stimulating and exosomal activities.

Leucine-rich glioma inactivated 3: a novel keratinocyte-derived melanogenic cytokine in vitiligo patients

BACKGROUND

In-vitro studies showed that Leucine-rich glioma inactivated 3 (LGI3) is a keratinocyte-derived cytokine that stimulates melanin synthesis and is increased after ultra violet B (UVB) irradiation. So, we postulated that LGI3 may be involved in vitiligo aetiopathogenesis and may participate in narrow band ultra violet B (NB-UVB) induced pigmentation in vitiligo.

OBJECTIVES

To assess this hypothesis, lesional LGI3 immunohistochemical expression of vitiligo patients before and after NB-UVB phototherapy was studied, and its correlation with repigmentation was evaluated.

METHODS

Forty vitiligo patients and 20 age, sex, and skin phenotype-matched controls were enrolled. Patients were treated with NB-UVB thrice weekly for 12 weeks. VASI score was evaluated before and after NB-UVB sessions. For vitiligo patients, baseline LGI3 immunohistochemical staining was estimated, and compared to that of controls and to its post-treatment data in those patients. Results: Baseline LGI3 immunohistochemical studied parameters (expression, intensity, percentage and H score) were significantly lower in vitiligo cases than controls (p=0.003, 0.013, 0.001 and 0.001 respectively). After 12 weeks of NB-UVB phototherapy, these LGI3 immunohistochemical parameters were up-regulated and became comparable to that of controls (p >0.05 for all). There was a significant positive correlation between the improvement of both VASI score and LGI3 H score mean values (r=-0.349 , p=0.027).

STUDY LIMITATIONS

Small number of investigated subjects.

CONCLUSIONS

Decreased LGI3 protein may play an active role in vitiligo pathogenesis and its up-regulation after NB-UVB phototherapy, may actively participate in NB-UVB photo-induced melanogenesis.

LGI3 is secreted and binds to ADAM22 via TRIF-dependent NF-κB pathway in response to LPS in human keratinocytes

Recently, we reported that HaCaT human keratinocytes secreted leucine-rich repeat LGI family member 3 (LGI3) protein after exposure to ultraviolet B (UVB) irradiation. In the present study, we aimed to determine whether LGI3 is also released in response to stimulation by lipopolysaccharides (LPS), membrane components of gram-negative bacteria. Our results showed that LGI3 was indeed secreted by LPS-stimulated HaCaT cells. We also found that LPS potently stimulated the induction of cycloxygenase-2 (COX-2), which is involved in the inflammatory response. In addition, LPS-induced LGI3 secretion and COX-2 expression were blocked by NS-398, a selective COX-2 inhibitor. Moreover, LPS activated nuclear factor-κB (NF-κB) via a TRIF-dependent pathway, and activated NF-κB led to LGI3 production in HaCaT cells. For the first time, we predicted the LGI3 promoter sequence and demonstrated that NF-κB bound to the LGI3 gene promoter region. LPS treatment also increased the expression of a disintegrin and metalloproteinase domain-containing protein 22 (ADAM22), a candidate LGI3 receptor. Furthermore, co-immunoprecipitation, flow cytometry, and immunocytochemistry revealed that LGI3 associated with ADAM22 in LPS-treated keratinocytes. Thus, ADAM22 may be an LGI3 receptor in human keratinocytes. Taken together, these data suggest that the TRIF-dependent pathway is a novel regulator of LGI3 secretion in response to LPS stimulation in HaCaT cells and that keratinocyte-derived LGI3 interacts with ADAM22 and mediates LPS-induced inflammation.

Leucine rich repeat LGI family member 3: Integrative analyses reveal its prognostic association with non-small cell lung cancer

Leucine rich repeat LGI family member 3 (LGI3) is a member of the LGI protein family. Our previous studies reported that LGI3 was expressed in adipose tissues, brain and skin, where it served roles as a multifunctional cytokine and pro-inflammatory adipokine. It was hypothesized that LGI3 may be involved in cytokine networks in cancer. The present study aimed to analyze differentially expressed genes in non-small cell lung cancer (NSCLC) tissues and NSCLC cohort data, to evaluate the prognostic role of LGI3. Expression microarray and NSCLC cohort data were statistically analyzed by bioinformatic methods, and protein-protein interactions, functional enrichment and pathway, gene coexpression network (GCN) and prognostic association analyses were performed. The results demonstrated that the expression levels of LGI3 and its receptor a disintegrin and metalloproteinase domain-containing protein 22 were significantly decreased in NSCLC tissues. A total of two upregulated genes and 11 downregulated genes in NSCLC tissues were identified as LGI3-regulated genes. Protein-protein interaction network analysis demonstrated that all LGI3-regulated genes that were altered in NSCLC were involved in a protein-protein interaction network cluster. Functional enrichment, Kyoto Encyclopedia of Genes and Genomes pathway and GCN analyses demonstrated the association of these genes with the immune and inflammatory responses, angiogenesis, the tumor necrosis factor pathway, and chemokine and peroxisome proliferator-activated receptor signaling pathways. Analysis of NSCLC cohorts revealed that low expression levels of LGI3 was significantly associated with poor prognosis of NSCLC. Analysis of the somatic mutations of the LGI3 gene in NSCLC revealed that the amino acid residues altered in NSCLC included two single nucleotide polymorphism sites and three phylogenetically coevolved amino acid residues. Taken together, these results suggest that LGI3 may be a potential prognostic marker of NSCLC.

Preconditioning with far-infrared irradiation enhances proliferation, cell survival, and migration of rat bone marrow-derived stem cells via CXCR4-ERK pathways

Far-infrared radiation (FIR) has been shown to exert positive effects on the cardiovascular system. However, the biological effects of FIR on bone marrow-derived stem cells (BMSCs) are not understood. In the present study, BMSCs were isolated from rat femur bone marrow and cultured in vitro. To investigate the effects of an FIR generator with an energy flux of 0.13 mW/cm² on rat BMSCs, survival of BMSCs was measured by crystal violet staining, and cell proliferation was additionally measured using Ez-Cytox cell viability, EdU, and Brd U assays. FIR preconditioning was found to significantly increase BMSC proliferation and survival against H₂O₂. The scratch and transwell migration assays showed that FIR preconditioning resulted in an increase in BMSC migration. qRT-PCR and Western blot analyses demonstrated that FIR upregulated Nanog, Sox2, c-Kit, Nkx2.5, and CXCR4 at both the mRNA and protein levels. Consistent with these observations, PD98059 (an ERK inhibitor) and AMD3100 (a CXCR4 inhibitor) prevented the activation of CXCR4/ERK and blocked the cell proliferation and migration induced by FIR. Overall, these findings provide the first evidence that FIR confers a real and significant benefit on the preconditioning of BMSCs, and might lead to novel strategies for improving BMSC therapy for cardiac ischemia.

Leucine-rich glioma inactivated 3: integrative analyses support its prognostic role in glioma

Background

Leucine-rich glioma inactivated 3 (LGI3) is a secreted protein member of LGI family. We previously reported that LGI3 was expressed in brain, adipose tissues and skin, where it played roles as a multifunctional cytokine. We postulated that LGI3 may be involved in cytokine network in cancers.

Aim

This study aimed to analyze differentially expressed genes in glioma tissues and glioma cohort data to investigate the prognostic role of LGI3 and its receptors.

Materials and methods

Expression microarray data from Gene Expression Omnibus and glioma cohort data were analyzed using bioinformatic tools for statistical analysis, protein–protein interactions, functional enrichment and pathway analyses and prognostic association analysis.

Results

We found that LGI3 and its receptors, ADAM22 and ADAM23, were significantly downregulated in glioma tissues. Eleven upregulated genes and two downregulated genes in glioma tissues were found to be the previously reported LGI3-regulated genes. Protein–protein interaction network analysis showed that 85% of the LGI3-regulated and glioma-altered genes formed a cluster of interaction network. Functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed the association of these genes with hypoxia responses, p53 and Akt signaling and various cancer-related pathways including glioma. Analysis of expression microarray data of glioma cohorts demonstrated that low expression levels of LGI3, ADAM22 and ADAM23 were significantly associated with poor prognosis of glioma.

Conclusion

These results propose that LGI3 and its receptors may play a prognostic role in glioma.

Leucine-rich glioma inactivated 3: Integrative analyses support its role in the cytokine network

Leucine-rich glioma inactivated (LGI)3 is a secreted protein member of LGI family. We previously repo-rted that LGI3 was upregulated in adipose tissues from obese mice and suppressed adipogenesis through its receptor, a disintegrin and metalloproteinase domain-containing protein 23 (ADAM23). We demonstrated that LGI3 regulated tumor necrosis factor-α and adiponectin, and proposed that LGI3 may be a pro-inflammatory adipokine involved in adipose tissue inflammation. In this study, we analyzed adipokine and cytokine profiles in LGI3 knockout mice and demonstrated that multiple factors were increased or decreased in the adipose tissues and plasma of the LGI3 knockout mice. Phosphoprotein array analysis revealed increases in the phosphorylation levels of Akt, AMP-activated protein kinase (AMPK), Bad, extracellular signal-regulated kinase (Erk)1/2, glycogen synthase kinase 3α (GSK3α), phosphatase and tensin homolog (PTEN) and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) in the LGI3-treated 3T3-L1 pre-adipocytes. Treatment with LGI3 increased the expression of various inflammatory genes in pre-adipocytes, adipocytes and macrophages. Integrative functional enrichment analysis for all LGI3-regulated gene products suggested their involvement in a number of biological processes, including cancer, inflammatory response, response to wounding, as well as cell proliferation and differentiation. Protein interaction network analysis of LGI3‑regulated gene products revealed that 94% of the gene products formed a cluster of interaction networks. Taken together, these results support the critical involvement of LGI3 in the cytokine network by interplaying with multiple adipokines, cytokines and signaling proteins.

Hepatic inflammatory cytokine production can be regulated by modulating sphingomyelinase and ceramide synthase 6

Chronic inflammation is associated with the pathogenesis of type 2 diabetes and diabetic complications, and palmitate has been nominated as a candidate for the molecular link between these disorders. Recently, a crucial role of ceramide in inflammation and metabolic diseases has been reported. Therefore, in this study, we investigated whether ceramide formation is involved in palmitate‑induced hepatic inflammation in vitro and in vivo. Ceramide can be generated either by the de novo pathway or by sphingomyelin degradation, and six different ceramide synthases (CerS) determine the specific acyl chain length of ceramide in mammals. We examined the roles of CerS and sphingomyelinases (SMases) in the secretion of inflammatory cytokines, such as tumour necrosis factor (TNF)‑α, interleukin (IL)‑1β, and IL‑6 in Hep3B cells. Among the six CerS, CerS6 overexpression uniquely elevated TNF‑α secretion via p38 mitogen‑activated protein kinase (MAPK) activation. In addition, the treatment of CerS6 overexpressing cells with palmitate synergistically increased cytokine secretion. However, neither palmitate treatment nor CerS6 overexpression altered lipopolysaccharide (LPS)-induced cytokine secretion. Instead, the activation of acidic (A)‑SMase was involved in LPS‑induced cytokine secretion via the MAPK/NF‑κB pathway. Finally, the suppression of ceramide generation via A‑SMase inhibition or de novo ceramide synthesis decreased high‑fat diet‑induced hepatic cytokine production in vivo. On the whole, our results revealed that CerS6 played a role in TNF‑α secretion, and palmitate augmented inflammatory responses in pathophysiological conditions in which CerS6 is overexpressed. In addition, A‑SMase activation was shown to be involved in LPS‑induced inflammatory processes, suggesting that the modulation of CerS6 and A‑SMase may be a therapeutic target for controlling hepatic inflammation.

LGI Proteins and Epilepsy in Human and Animals

Leucine‐rich glioma‐inactivated (LGI) protein was first thought to have a suppressor effect in the formation of some cancers. Developments in physiology and medicine made it possible to characterize the function of the LGI protein family and its crucial role in different conditions more precisely. These proteins play an important role in synaptic transmission, and dysfunction may cause hyperexcitability. Genetic mutation of LGI1was confirmed to be the cause of autosomal dominant lateral temporal lobe epilepsy in humans. The LGI2 mutation was identified in benign familial juvenile epilepsy in Lagotto Romagnolo (LR) dogs. Cats with familial spontaneous temporal lobe epilepsy have been reported, and the etiology might be associated with LGI protein family dysfunction. In addition, an autoimmune reaction against LGI1 was detected in humans and cats with limbic encephalitis. These advances prompted a review of LGI protein function and its role in different seizure disorders.

Leucine-rich glioma inactivated 3 and tumor necrosis factor-α regulate mutually through NF-κB

Leucine-rich glioma inactivated 3 (LGI3) is a secreted protein member of LGI family. We previously reported that LGI3 increased in obese adipose tissues and suppressed adipogenesis through its receptor, ADAM23. We proposed that LGI3 may be a pro-inflammatory adipokine secreted predominantly by preadipocytes and macrophages. In this study, we showed that LGI3 and tumor necrosis factor-α (TNF-α) upregulated each other in 3T3-L1 cells. Treatment of 3T3-L1 preadipocytes with LGI3 protein increased TNF-α mRNA and protein. LGI3 treatment led to NF-κB activation and binding to an NF-κB binding site (-523 to -514) in TNF-α promoter. TNF-α treatment increased mRNA and protein expression of LGI3 and ADAM23. TNF-α increased NF-κB binding to a predicted binding site (-40 to -31) in LGI3 promoter. High fat diet-fed mice showed that LGI3 and TNF-α were increased and colocalized in adipose tissue inflammation. Taken together, these results suggested that mutual upregulation of LGI3 and TNF-α may play a role in adipose tissue inflammation in obesity.