Characteristic and fate determination of adipose precursors during adipose tissue remodeling

Adipose tissues are essential for actively regulating systemic energy balance,glucose homeostasis,immune responses,reproduction,and longevity.Adipocytes maintain dynamic metabolic needs and possess heterogeneity in energy storage and supply.Overexpansion of adipose tissue,especially the visceral type,is a high risk for diabetes and other metabolic diseases.Changes in adipocytes,hypertrophy or hyperplasia,contribute to the remodeling of obese adipose tissues,accompanied by abundant immune cell accumulation,decreased angiogenesis,and aberrant extracellular matrix deposition.The process and mechanism of adipogenesis are well known,however,adipose precursors and their fate decision are only being defined with recent information available to decipher how adipose tissues generate,maintain,and remodel.Here,we discuss the key findings that identify adipose precursors phenotypically,with special emphasis on the intrinsic and extrinsic signals in instructing and regulating the fate of adipose precursors under pathophysiological conditions.We hope that the information in this review lead to novel therapeutic strategies to combat obesity and related metabolic diseases.

Incubation and application of transgenic green fluorescent nude mice in visualization studies on glioma tissue remodeling

Background The primary reasons for local recurrence and therapeutic failure in the treatment of malignant gliomas are the invasion and interactions of tumor cells with surrounding normal brain cells. However, these tumor cells are hard to be visualized directly in histopathological preparations, or in experimental glioma models. Therefore, we developed an experimental human dual-color in vivo glioma model, which made tracking solitary invasive glioma cells possible, for the purpose of visualizing the interactions between red fluorescence labeled human glioma cells and host brain cells. This may offer references for further studying the roles of tumor microenvironment during glioma tissue remodeling. Methods Transgenic female C57BL/6 mice expressing enhanced green fluorescent protein （EGFP） were crossed with male Balb/c nude mice. Then sib mating was allowed to occur continuously in order to establish an inbred nude mice strain with 50% of their offspring that are EGFP positive. Human glioma cell lines U87-MG and SU3 were transfected with red fluorescent protein （RFP） gene, and a rat C6 glioma cell line was stained directly with CM-Dil, to establish three glioma cell lines emitting red fluorescence （SU3-RFP, U87-RFP, and C6-CM-Dil）. Red fluorescence tumor cells were inoculated via intra-cerebral injection into caudate nucleus of the EGFP nude mice. Tumor-bearing mice were sacrificed when their clinical symptoms appeared, and the whole brain was harvested and snap frozen for further analysis. Confocal laser scanning microscopy was performed to monitor the mutual interactions between tumor cells and host brain cells. Results Almost all the essential tissues of the established EGFP athymic Balb/c nude mice, except hair and erythrocytes, fluoresced green under excitation using a blue light-emitting flashlight with a central peak of 470 nm, approximately 50% of the offsprings were nu/nu EGFP＋. SU3-RFP, U87-RFP, and C6-CM-Dil almost 100% expressed red fluorescence under the fluorescence microscope. Under fluorescence microscopic view, RFP＋ cells were observed growing wherever they arrived at, locating in the brain parenchyma, ventricles, and para-vascular region. The interactions between the transplanted tumor cells and host adjacent cells could be classified into three types： （1） interweaving; （2） mergence; and （3） fusion. Interweaving was observed in the early stage of tumor remodeling, in which both transplantable tumor cells and host cells were observed scattered in the tumor invading and spreading area without organic connections. Mergence was defined as mutual interactions between tumor cells and host stroma during tumorigenesis. Direct cell fusion between transplantable tumor cells and host cells could be observed occasionally. Conclusions This study showed that self-established EGFP athymic nude mice offered the possibility of visualizing tumorigenesis of human xenograft tumor, and the dual-color xenograft glioma model was of considerable utility in studying the process of tumor remodeling. Based on this platform, mutual interactions between glioma cells and host tissues could be observed directly to further elucidate the development of tumor microenvironment.

Whole wheat flour coating with antioxidant property accelerates tissue remodeling for enhanced wound healing

As a daily food for billions of people for thousands of years,whole grain is rich in phenolic compounds and may have huge potentials to provide natural antioxidants.Herein,owing to the significant biomedical potential,the effect of whole wheat flour solution as antioxidant wound coating for enhanced wound healing has been studied.The results show that the low concentration of whole wheat flour solutions have good biocompatibility and can scavenge radical and intracellular ROS in vitro,accelerating tissue remodeling in vivo to promote wound healing.This kind of whole wheat flour solution has great potential application for cutaneous wound repair.

Research advances in smart responsive-hydrogel dressings with potential clinical diabetic wound healing properties

The treatment of chronic and non-healing wounds in diabetic patients remains a major medical problem.Recent reports have shown that hydrogel wound dressings might be an effective strategy for treating diabetic wounds due to their excellent hydrophilicity,good drug-loading ability and sustained drug release properties.As a typical example,hyaluronic acid dressing(Healoderm)has been demonstrated in clinical trials to improve wound-healing efficiency and healing rates for diabetic foot ulcers.However,the drug release and degradation behavior of clinically-used hydrogel wound dressings cannot be adjusted according to the wound microenvironment.Due to the intricacy of diabetic wounds,antibiotics and other medications are frequently combined with hydrogel dressings in clinical practice,although these medications are easily hindered by the hostile environment.In this case,scientists have created responsive-hydrogel dressings based on the microenvironment features of diabetic wounds(such as high glucose and low pH)or combined with external stimuli(such as light or magnetic field)to achieve controllable drug release,gel degradation,and microenvironment improvements in order to overcome these clinical issues.These responsive-hydrogel dressings are anticipated to play a significant role in diabetic therapeutic wound dressings.Here,we review recent advances on responsive-hydrogel dressings towards diabetic wound healing,with focus on hydrogel structure design,the principle of responsiveness,and the behavior of degradation.Last but not least,the advantages and limitations of these responsive-hydrogels in clinical applications will also be discussed.We hope that this review will contribute to furthering progress on hydrogels as an improved dressing for diabetic wound healing and practical clinical application.

Remodeling of skin nerve fibers during burn wound healing

Burn wound healing involves a complex sequence of processes. Recent studies have revealed that skin reinnervation may have an impact on physiological wound repair. Few studies have addressed the process of reinnervation and morphological changes in regenerated nerve fibers. The regeneration of neurites during full-thickness burn wound healing was determined by immunofluorescent staining using an anti-neurofilament protein monoclonal antibody, and three-dimensional morphology was observed under a laser scanning confocal microscope. Morphology and the volume fraction of collagen and nerve fibers were measured. Skin reinnervation increased during wound healing, peaked during the proliferative scar stage, and then decreased to lower levels during the maturation period. The results from the skin nerve fibers correlated with those from collagen using semi-quantitative analysis. Disintegration and fragmentation were observed frequently in samples from the proliferative stage, and seldom occurred during the maturation stage. There was a remodeling process of regenerated nerve fibers during wound healing, which comprised changed innervation density and topical morphology. The mechanism of remodeling for nerve fibers requires further investigation.

Construction of Oriented Structure in Inner Surface of Small-Diameter Artificial Blood Vessels:A Review

There is an urgent need for small-diameter artificial blood vessels in clinic.Physical,chemical and biological factors should be integrated to avoid thrombosis and intimal hyperplasia after implantation and to promote successful fabrication of small-diameter artificial blood vessels.From a physical perspective,the internal oriented structures of natural blood vessels plays an important role in guiding the directional growth of cells,improving the blood flow environment,and promoting the regeneration of vascular tissue.In this review,the effects of the oriented structures on cells,including endothelial cells(ECs),smooth muscle cells(SMCs)and stem cells,as well as the effect of the oriented structures on hemodynamics and vascular tissue remodeling and regeneration are introduced.Various forms of oriented structures(fibers,grooves,channels,etc.)and their construction methods are also reviewed.Conclusions and future perspectives are given.It is expected to give some references to relevant researches.

A decellularized nerve matrix scaffold inhibits neuroma formation in the stumps of transected peripheral nerve after peripheral nerve injury

Traumatic painful neuroma is an intractable clinical disease characterized by improper extracellular matrix(ECM)deposition around the injury site.Studies have shown that the microstructure of natural nerves provides a suitable microenvironment for the nerve end to avoid abnormal hyperplasia and neuroma formation.In this study,we used a decellularized nerve matrix scaffold(DNM-S)to prevent against the formation of painful neuroma after sciatic nerve transection in rats.Our results showed that the DNM-S effectively reduced abnormal deposition of ECM,guided the regeneration and orderly arrangement of axon,and decreased the density of regenerated axons.The epineurium-perilemma barrier prevented the invasion of vascular muscular scar tissue,greatly reduced the invasion ofα-smooth muscle actin-positive myofibroblasts into nerve stumps,effectively inhibited scar formation,which guided nerve stumps to gradually transform into a benign tissue and reduced pain and autotomy behaviors in animals.These findings suggest that DNM-S-optimized neuroma microenvironment by ECM remodeling may be a promising strategy to prevent painful traumatic neuromas.

Capturing dynamic biological signals via bio-mimicking hydrogel for precise remodeling of soft tissue

Soft tissue remodeling is a sophisticated process that sequentially provides dynamic biological signals to guide cell behavior.However,capturing these signals within hydrogel and directing over time has still been unrealized owing to the poor comprehension of physiological processes.Here,a bio-mimicking hydrogel is designed via thiol-ene click reaction to capture the early physical signal triggered by inflammation,and the chemical signals provided with chemokine and natural adhesion sites,which guaranteed the precise soft tissue remodeling.This bio-mimicking hydrogel efficiently facilitated cell anchoring,migration,and invasion in the 3D matrix due to the permissive space and the interaction with integrin receptors.Besides,the covalently grafted chemokine-like peptide is optimal for colonization and functional differentiation of endothelial cells through a HIF-1αdependent signal pathway.Furthermore,the early polarization of macrophages,collagen deposition and angiogenesis in rat acute wound model,and the increased blood perfusion in mouse skin flap model have confirmed that the bio-mimicking hydrogel realized precise soft tissue remodeling and opens new avenues for the phased repair of different tissues such as nerve,myocardium,and even bone.

Insight into molecular mechanisms underlying hepatic dysfunction in severe COVID-19 patients using systems biology

BACKGROUND The coronavirus disease 2019(COVID-19),a pandemic contributing to more than 105 million cases and more than 2.3 million deaths worldwide,was described to be frequently accompanied by extrapulmonary manifestations,including liver dysfunction.Liver dysfunction and elevated liver enzymes were observed in about 53%of COVID-19 patients.AIM To gain insight into transcriptional abnormalities in liver tissue of severe COVID-19 patients that may result in liver dysfunction.METHODS The transcriptome of liver autopsy samples from severe COVID-19 patients against those of non-COVID donors was analyzed.Differentially expressed genes were identified from normalized RNA-seq data and analyzed for the enrichment of functional clusters and pathways.The differentially expressed genes were then compared against the genetic signatures of liver diseases including cirrhosis,fibrosis,non-alcoholic fatty liver disease(NAFLD),and hepatitis A/B/C.Gene expression of some differentially expressed genes was assessed in the blood samples of severe COVID-19 patients with liver dysfunction using qRT-PCR.RESULTS Analysis of the differential transcriptome of the liver tissue of severe COVID-19 patients revealed a significant upregulation of transcripts implicated in tissue remodeling including G-coupled protein receptors family genes,DNAJB1,IGF2,EGFR,and HDGF.Concordantly,the differential transcriptome of severe COVID-19 liver tissues substantially overlapped with the disease signature of liver diseases characterized with pathological tissue remodeling(liver cirrhosis,Fibrosis,NAFLD,and hepatitis A/B/C).Moreover,we observed a significant suppression of transcripts implicated in metabolic pathways as well as mitochondrial function,including cytochrome P450 family members,ACAD11,CIDEB,GNMT,and GPAM.Consequently,drug and xenobiotics metabolism pathways are significantly suppressed suggesting a decrease in liver detoxification capacity.In correspondence with the RNA-seq data analysis,we observed a significant upregulation of DNAJB1 and HSP90AB1 as well as significant downregulation of CYP39A1 in the blood plasma of severe COVID-19 patients with liver dysfunction.CONCLUSION Severe COVID-19 patients appear to experience significant transcriptional shift that may ensue tissue remodeling,mitochondrial dysfunction and lower hepatic detoxification resulting in the clinically observed liver dysfunction.

Serological biomarkers for management of primary sclerosing cholangitis

Clinical manifestations and progression of primary sclerosing cholangitis(PSC)are heterogeneous,and its pathogenesis is poorly understood.The importance of gut-liver interactions in the pathogenesis has been clinically confirmed and highlighted in different theories.Recent advances regarding biomarkers of biliarygut crosstalk may help to identify clinically relevant PSC subgroups assisting everyday clinical work-up(e.g.,diagnosis,disease stratification,or surveillance)and the exploration of potential therapeutic targets.Alkaline phosphatase produced by the biliary epithelium is consistently associated with prognosis.However,its level shows natural fluctuation limiting its use in individual patients.Inflammatory,cell activation,and tissue remodeling markers have been reported to predict clinical outcome.Elevated immunoglobulin(Ig)G4 level is associated with a shorter transplantation-free survival.IgG type atypical perinuclear anti-neutrophil cytoplasmic antibodies(P-ANCAs)are non-specific markers of various autoimmune liver diseases and may reflect an abnormal B-cell response to gut microbial antigens.IgG type atypical P-ANCA identifies PSC patients with particular clinical and genetic(for human leukocyte antigens)characteristics.The presence of IgA type anti-F-actin antibody(AAA)may predict a progressive disease course,and it is associated with enhanced mucosal immune response to various microbial antigens and enterocyte damage.IgA type anti-glycoprotein 2(GP2)antibodies identify patients with a severe disease phenotype and poor survival due to enhanced fibrogenesis or development of cholangiocarcinoma.Elevated soluble vascular adhesion protein-1(sVAP-1)level is associated with adverse disease outcomes in PSC.High sVAP-1 levels correlate with mucosal addressin cell adhesion molecule-1(MAdCAM-1)expression in the liver that contributes to gut activated T-cell homing to the hepatobiliary tract.In the present paper,we review the evidence on these possible serological markers that could potentially help address the unmet clinical needs in PSC.

Acetylation of PPARγin macrophages promotes visceral fat degeneration in obesity

Obesity is characterized by chronic,low-grade inflammation,which is driven by macrophage infiltration of adipose tissue.PPARγ is well established to have an anti-inflammatory function in macrophages,but the mechanism that regulates its function in these cells remains to be fully elucidated.PPARγundergoes post-translational modifications(PTMs),including acetylation,to mediate ligand responses,including on metabolic functions.Here,we report that PPARγacetylation in macrophages promotes their infiltration into adipose tissue,exacerbating metabolic dysregulation.We generated a mouse line that expresses a macrophage-specific,constitutive acetylation-mimetic form of PPARγ(K293Q^(flox/flox):LysM-cre,mK293Q)to dissect the role of PPARγacetylation in macrophages.Upon highfat diet feeding to stimulate macrophage infiltration into adipose tissue,we assessed the overall metabolic profile and tissue-specific phenotype of the mutant mice,including responses to the PPARγagonist Rosiglitazone.Macrophage-specific PPARγK293Q expression promotes proinflammatory macrophage infiltration and fibrosis in epididymal white adipose tissue,but not in subcutaneous or brown adipose tissue,leading to decreased energy expenditure,insulin sensitivity,glucose tolerance,and adipose tissue function.Furthermore,mK293Q mice are resistant to Rosiglitazone-induced improvements in adipose tissue remodeling.Our study reveals that acetylation is a new layer of PPARγregulation in macrophage activation,and highlights the importance and potential therapeutic implications of such PTMs in regulating metabolism.

Myeloid-specific expression of Stat3C results in conversion of bone marrow mesenchymal stem cells into alveolar type Ⅱ epithelial cells in the lung

Bone marrow mesenchymal stem cells (BMSCs) and myeloid lineage cells originate from the bone marrow, and influence each other in vivo. To elucidate the mechanism that controls the interrelationship between these two cell types, the signaling path- way of signal transducer and activator of transcription 3 (Stat3) was activated by overexpressing Stat3C in a newly established c-fms-rtTA/(TetO)7-CMV-Stat3C bitransgenic mouse model, In this system, Stat3C-Flag fusion protein was overexpressed in myeloid lineage cells after doxycycline treatment. Stat3C overexpression induced systematic elevation of macrophages and neutrophils in multiple organs. In the lung, tissue neoplastic pneumocyte proliferation was observed. After in vitro cultured hSP-B 1.5-kb lacZ BMSCs were injected into the bitransgenic mice, BMSCs were able to repopulate in multiple organs, self-renew in the bone marrow and spleen, and convert into alveolar type II epithelial cells. The bone marrow transplantation study indicated that increases of myeloid lineage cells and BMSC-AT II cell conversion were due to malfunction of myeloid progenitor cells as a result of Stat3C overexpression. The study supports the concept that activation of the Stat3 pathway in myeloid cells plays an important role in BMSC function, including homing, repopulating and converting into residential AT II epithelial cells in the lung.