Boosting cartilage repair with silk fibroin-DNA hydrogel-based cartilage organoid precursor

Osteoarthritis (OA), a common degenerative disease, is characterized by high disability and imposes substantial economic impacts on individuals and society. Current clinical treatments remain inadequate for effectively managing OA. Organoids, miniature 3D tissue structures from directed differentiation of stem or progenitor cells, mimic native organ structures and functions. They are useful for drug testing and serve as active grafts for organ repair. However, organoid construction requires extracellular matrix-like 3D scaffolds for cellular growth. Hydrogel microspheres, with tunable physical and chemical properties, show promise in cartilage tissue engineering by replicating the natural microenvironment. Building on prior work on SF-DNA dual-network hydrogels for cartilage regeneration, we developed a novel RGD-SF-DNA hydrogel microsphere (RSD-MS) via a microfluidic system by integrating photopolymerization with self-assembly techniques and then modified with Pep-RGDfKA. The RSD-MSs exhibited uniform size, porous surface, and optimal swelling and degradation properties. In vitro studies demonstrated that RSD-MSs enhanced bone marrow mesenchymal stem cells (BMSCs) proliferation, adhesion, and chondrogenic differentiation. Transcriptomic analysis showed RSD-MSs induced chondrogenesis mainly through integrin-mediated adhesion pathways and glycosaminoglycan biosynthesis. Moreover, in vivo studies showed that seeding BMSCs onto RSD-MSs to create cartilage organoid precursors (COPs) significantly enhanced cartilage regeneration. In conclusion, RSD-MS was an ideal candidate for the construction and long-term cultivation of cartilage organoids, offering an innovative strategy and material choice for cartilage regeneration and tissue engineering.

Synthetic biology-based bacterial extracellular vesicles displaying BMP-2 and CXCR4 to ameliorate osteoporosis

Osteoporosis (OP) is a systematic bone disease characterized by low bone mass and fragile bone microarchitecture. Conventional treatment for OP has limited efficacy and long-term toxicity. Synthetic biology makes bacterial extracellular vesicle (BEVs)-based therapeutic strategies a promising alternative for the treatment of OP. Here, we constructed a recombinant probiotics Escherichia coli Nissle 1917-pET28a-ClyA-BMP-2-CXCR4 (ECN-pClyA-BMP-2-CXCR4), in which BMP-2 and CXCR4 were overexpressed in fusion with BEVs surface protein ClyA. Subsequently, we isolated engineered BEVs-BMP-2-CXCR4 (BEVs-BC) for OP therapy. The engineered BEVs-BC exhibited great bone targeting in vivo. In addition, BEVs-BC had good biocompatibility and remarkable ability to promote osteogenic differentiation of BMSCs. Finally, the synthetic biology-based BEVs-BC significantly prevented the OP in an ovariectomized (OVX) mouse model. In conclusion, we constructed BEVs-BC with both bone-targeting and bone-forming in one-step using synthetic biology, which provides an effective strategy for OP and has great potential for industrialization.

Expert consensus on Prospective Precision Diagnosis and Treatment Strategies for Osteoporotic Fractures

Osteoporotic fractures are the most severe complications of osteoporosis, characterized by poor bone quality, difficult realignment and fixation, slow fracture healing, and a high risk of recurrence. Clinically managing these fractures is relatively challenging, and in the context of rapid aging, they pose significant social hazards. The rapid advancement of disciplines such as biophysics and biochemistry brings new opportunities for future medical diagnosis and treatment. However, there has been limited attention to precision diagnosis and treatment strategies for osteoporotic fractures both domestically and internationally. In response to this, the Chinese Medical Association Orthopaedic Branch Youth Osteoporosis Group, Chinese Geriatrics Society Geriatric Orthopaedics Committee, Chinese Medical Doctor Association Orthopaedic Physicians Branch Youth Committee Osteoporosis Group, and Shanghai Association of Integrated Traditional Chinese and Western Medicine Osteoporosis Professional Committee have collaborated to develop this consensus. It aims to elucidate emerging technologies that may play a pivotal role in both diagnosis and treatment, advocating for clinicians to embrace interdisciplinary approaches and incorporate these new technologies into their practice. Ultimately, the goal is to improve the prognosis and quality of life for elderly patients with osteoporotic fractures.

Super-resolution imaging of folate receptor alpha on cell membranes using peptide-based probes

Folate receptor alpha (FRα) is a vital membrane protein which have great association with cancers and involved in various biological processes including folate transport and cell signaling. However, the distribution and organization pattern of FRα on cell membranes remains unclear. Previous studies relied on antibodies to recognize the proteins. However, multivalent crosslinking and large size of antibodies confuse the direct observation to some extent. Fortunately, the emergence of peptide, which are small-sized and monovalent, has supplied us an unprecedented choice. Here, we applied fluorophore-conjugated peptide probe to recognize the FRα and study the distribution pattern of FRα on cell membrane using dSTORM super-resolution imaging technique. FRα were found to organized as clusters on cell surface with different sizes. And they have a higher expression level and formed larger clusters on various cancer cells than normal cells, which hinted that its specific distribution could be utilized for cancer diagnosis. Furthermore, we revealed that the lipid raft and cortical actin as restrictive factors for the FRα clustering, suggesting a potential assembly mechanism insight into FRα clustering on cell membrane. Collectively, our work clarified the morphology distribution and clustered organization of FRα with peptide probes at the nanometer scale, which paves the way for further revealing the relationship between the spatial organization and functions of membranal proteins.

Extracellular derivatives for bone metabolism

BACKGROUND

Bone metabolism can maintain the normal homeostasis and function of bone tissue. Once the bone metabolism balance is broken, it will cause osteoporosis, osteoarthritis, bone defects, bone tumors, or other bone diseases. However, such orthopedic diseases still have many limitations in clinical treatment, such as drug restrictions, drug tolerance, drug side effects, and implant rejection.

AIM OF REVIEW

In complex bone therapy and bone regeneration, extracellular derivatives have become a promising research focus to solve the problems of bone metabolic diseases. These derivatives, which include components such as extracellular matrix, growth factors, and extracellular vesicles, have significant therapeutic potential. It has the advantages of good biocompatibility, low immune response, and dynamic demand for bone tissue. The purpose of this review is to provide a comprehensive perspective on extracellular derivatives for bone metabolism and elucidate the intrinsic properties and versatility of extracellular derivatives. Further discussion of them as innovative advanced orthopedic materials for improving the effectiveness of bone therapy and regeneration processes.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this review, we first listed the types and functions of three extracellular derivatives. Then, we discussed the effects of extracellular derivatives of different cell sources on bone metabolism. Subsequently, we collected applications of extracellular derivatives in the treatment of bone metabolic diseases and summarized the advantages and challenges of extracellular derivatives in clinical applications. Finally, we prospected the extracellular derivatives in novel orthopedic materials and clinical applications. We hope that the comprehensive understanding of extracellular derivatives in bone metabolism will provide new solutions to bone diseases.

M2 macrophage-derived exosomes promote diabetic fracture healing by acting as an immunomodulator

Diabetes mellitus is a chronically inflamed disease that predisposes to delayed fracture healing. Macrophages play a key role in the process of fracture healing by undergoing polarization into either M1 or M2 subtypes, which respectively exhibit pro-inflammatory or anti-inflammatory functions. Therefore, modulation of macrophage polarization to the M2 subtype is beneficial for fracture healing. Exosomes perform an important role in improving the osteoimmune microenvironment due to their extremely low immunogenicity and high bioactivity. In this study, we extracted the M2-exosomes and used them to intervene the bone repair in diabetic fractures. The results showed that M2-exosomes significantly modulate the osteoimmune microenvironment by decreasing the proportion of M1 macrophages, thereby accelerating diabetic fracture healing. We further confirmed that M2-exosomes induced the conversion of M1 macrophages into M2 macrophages by stimulating the PI3K/AKT pathway. Our study offers a fresh perspective and a potential therapeutic approach for M2-exosomes to improve diabetic fracture healing.

Microenvironment-targeted strategy steers advanced bone regeneration

Treatment of large bone defects represents a great challenge in orthopedic and craniomaxillofacial surgery. Traditional strategies in bone tissue engineering have focused primarily on mimicking the extracellular matrix (ECM) of bone in terms of structure and composition. However, the synergistic effects of other cues from the microenvironment during bone regeneration are often neglected. The bone microenvironment is a sophisticated system that includes physiological (e.g., neighboring cells such as macrophages), chemical (e.g., oxygen, pH), and physical factors (e.g., mechanics, acoustics) that dynamically interact with each other. Microenvironment-targeted strategies are increasingly recognized as crucial for successful bone regeneration and offer promising solutions for advancing bone tissue engineering. This review provides a comprehensive overview of current microenvironment-targeted strategies and challenges for bone regeneration and further outlines prospective directions of the approaches in construction of bone organoids.

Bone/cartilage organoid on-chip: Construction strategy and application

The necessity of disease models for bone/cartilage related disorders is well-recognized, but the barrier between ex-vivo cell culture, animal models and the real human body has been pending for decades. The organoid-on-a-chip technique showed opportunity to revolutionize basic research and drug screening for diseases like osteoporosis and arthritis. The bone/cartilage organoid on-chip (BCoC) system is a novel platform of multi-tissue which faithfully emulate the essential elements, biologic functions and pathophysiological response under real circumstances. In this review, we propose the concept of BCoC platform, summarize the basic modules and current efforts to orchestrate them on a single microfluidic system. Current disease models, unsolved problems and future challenging are also discussed, the aim should be a deeper understanding of diseases, and ultimate realization of generic ex-vivo tools for further therapeutic strategies of pathological conditions.

Maintaining hypoxia environment of subchondral bone alleviates osteoarthritis progression

Abnormal subchondral bone remodeling featured by overactivated osteoclastogenesis leads to articular cartilage degeneration and osteoarthritis (OA) progression, but the mechanism is unclear. We used lymphocyte cytosolic protein 1 (Lcp1) knockout mice to suppress subchondral osteoclasts in a mice OA model with anterior cruciate ligament transection (ACLT), and Lcp1^-/- mice showed decreased bone remodeling in subchondral bone and retarded cartilage degeneration. For mechanisms, the activated osteoclasts in subchondral bone induced type-H vessels and elevated oxygen concentration, which ubiquitylated hypoxia-inducible factor 1 alpha subunit (HIF-1α) in chondrocytes and led to cartilage degeneration. Lcp1 knockout impeded angiogenesis, which maintained hypoxia environment in joints and delayed the OA progression. Stabilization of HIF-1α delayed cartilage degeneration, and knockdown of Hif1a abolished the protective effects of Lcp1 knockout. Last, we showed that Oroxylin A, an Lcp1-encoded protein l-plastin (LPL) inhibitor, could alleviate OA progression. In conclusion, maintaining hypoxic environment is an attractive strategy for OA treatment.

[Reclassification of flat type sudden deafness]

Objective: To reclassify the flat type sudden deafness according to the types of audiogram shape, and to explore the correlation between different pattern of hearing loss and prognosis. Methods: All of 1 024 patients with unilateral sudden deafness (492 males and 532 females, aged from 19 to 65 years, with an average age of 41.2 years old) admitted to 33 hospitals nationwide from August 2007 to October 2011 were divided into four types according to Chinese Guideline of Sudden Deafness(2015): low-frequency, high-frequency, flat and total deafness. Then, 402 patients with flat type sudden deafness were further divided into ascending type, descending type and consistent type according to the audiogram shapes. First, we compared the clinical characteristics and prognosis among these three subtypes of flat deafness, then compared the clinical characteristics and prognosis between ascending flat deafness and low-frequency deafness, descending flat deafness and high-frequency deafness, consistent flat deafness and total deafness, explored the factors related to the prognosis of flat deafness. SPSS 21.0 software, ANOVA, χ² test, t-test and Logistic regression were used to analyze the data. Results: The cure rates of flat ascending, flat descending and flat consistent sudden deafness groups were 70.7%, 17.1% and 34.0% respectively, with a statistically significant difference (χ²=33.984, P<0.001); However, there was no significant difference in age, sex and affected side (all P>0.05). The independent related factors for the recovery of flat type sudden deafness were as follows: whether there was dizziness [OR=0.459; 95% confidence interval (CI): 0.271-0.777], the type of audiogram shape (OR=0.721; 95%CI: 0.530-0.981), and days from onset to therapy (OR=0.903, 95%CI: 0.835-0.978), all of which had P values<0.05. There was no significant difference in the cure rates between ascending flat sudden deafness and low-frequency descending sudden deafness, descending flat sudden deafness and high-frequency descending sudden deafness (all P>0.05). The pure tone average(PTA) of flat consistent sudden deafness and total deafness were (69.1±18.9) and (101.7±17.7) dB HL, respectively, with a statistically significant difference (t=20.890, P<0.001), and the cure rates were 34.0% and 14.5%, respectively, with a statistically significant difference (χ²=29.012, P<0.001). Conclusion: According to the audiogram shape, the flat type sudden deafness can be further divided into ascending flat sudden deafness, descending flat sudden deafness and consistent flat sudden deafness, which can more effectively evaluate the prognosis. The cure rate of ascending flat sudden deafness is similar to that of low-frequency sudden deafness, and the prognosis is well; The cure rate of descending flat sudden deafness is similar to that of high-frequency descending sudden deafness, and the prognosis is poor. The cure rate of consistent flat sudden deafness is higher than that of total deafness. PTA plays an important role in the prognosis of consistent flat sudden deafness and total deafness. Total deafness can be regarded as a single type of sudden deafness.

Selection and identification of a novel ssDNA aptamer targeting human skeletal muscle

Skeletal muscle disorders have posed great threats to health. Selective delivery of drugs and oligonucleotides to skeletal muscle is challenging. Aptamers can improve targeting efficacy. In this study, for the first time, the human skeletal muscle-specific ssDNA aptamers (HSM01, etc.) were selected and identified with Systematic Evolution of Ligands by Exponential Enrichment (SELEX). The HSM01 ssDNA aptamer preferentially interacted with human skeletal muscle cells in vitro. The in vivo study using tree shrews showed that the HSM01 ssDNA aptamer specifically targeted human skeletal muscle cells. Furthermore, the ability of HSM01 ssDNA aptamer to target skeletal muscle cells was not affected by the formation of a disulfide bond with nanoliposomes in vitro or in vivo, suggesting a potential new approach for targeted drug delivery to skeletal muscles via liposomes. Therefore, this newly identified ssDNA aptamer and nanoliposome modification could be used for the treatment of human skeletal muscle diseases.

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Using SELEX, our study selected and identified a human skeletal muscle-specific ssDNA aptamer.

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HSM01 ssDNA aptamer preferentially interacts with human skeletal muscle cells in vitro and in vivo.

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When linked with nanoliposomes, the skeletal muscle cells targeting ability still remains the same.

[The peripheral blood inflammatory markers in Ménière's disease patients with and without migraine]

Objective: To investigate the peripheral blood inflammatory markers including white blood cell count (WBC), monocytes, neutrophils, lymphocytes, platelets, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), high-density lipoprotein(HDL-C), low-density lipoprotein and fibrinogen (FIB) in Ménière's disease (MD) patients with and without migraine, and to explore the relationship between the inflammatory response with MD and migraine. Methods: The general physical condition, clinical manifestations, pure-tone audiometry, and peripheral blood inflammatory markers of 92 unilateral MD patients who were hospitalized in Peking University People's Hospital for surgical treatment from January 2017 to January 2021 were continuously collected. Meanwhile, 50 healthy controls matched with age and sex were included, and their general physical conditions and peripheral blood inflammatory markers were also collected. This study consisted of two parts. First, the differences in epidemical characteristics and peripheral blood inflammatory markers between MD patients and healthy controls were compared by univariate analysis. Second, all 92 MD patients were divided into two subgroups according to whether they were accompanied by migraine. The clinical characteristics and peripheral blood inflammatory markers of MD patients with and without migraine were compared by univariate analysis. Thereafter, binary Logistic regression was used to analyze the related factors of whether MD patients were accompanied with migraine. Results: Compared with the healthy control group, the peripheral blood WBC, neutrophils and FIB of MD patients were significantly increased (all P<0.05). Compared with MD patients without migraine, MD patients with migraine had higher female prevalence, longer disease history, lower low-frequency hearing threshold, higher frequency of vertigo attacks and higher HDL-C levels (all P<0.05), meanwhile, female, frequency of vestibular attacks and HDL-C were independent related factors of whether MD patients were accompanied with migraine. Conclusion: The occurrence of MD and migraine may be related to the inflammatory response. The level of anti-inflammatory factors in the blood of MD patients with migraine are higher, suggesting that the inflammatory response status of MD patients with and without migraine is different.

Revealing the structure and organization of intercellular tunneling nanotubes (TNTs) by STORM imaging

Tunneling nanotubes (TNTs) are nanoscale, actin-rich, transient intercellular tubes for cell-to-cell communication, which transport various cargoes between distant cells. The structural complexity and spatial organization of the involved components of TNTs remain unknown. In this work, the STORM super-resolution imaging technique was applied to elucidate the structural organization of microfilaments and microtubules in intercellular TNTs at the nanometer scale. Our results reveal different distributions of microfilaments and intertwined structures of microtubules in TNTs, which promote the knowledge of TNT communications.

Bacterial extracellular vesicles as bioactive nanocarriers for drug delivery: Advances and perspectives

Nanosized extracellular vesicles derived from bacteria contain diverse cargo and transfer intercellular bioactive molecules to cells. Due to their favorable intercellular interactions, cell membrane-derived bacterial extracellular vesicles (BEVs) have great potential to become novel drug delivery platforms. In this review, we summarize the biogenesis mechanism and compositions of various BEVs. In addition, an overview of effective isolation and purification techniques of BEVs is provided. In particular, we focus on the application of BEVs as bioactive nanocarriers for drug delivery. Finally, we summarize the advances and challenges of BEVs after providing a comprehensive discussion in each section. We believe that a deeper understanding of BEVs will open new avenues for their exploitation in drug delivery applications.

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Bacterial extracellular vesicles (BEVs) are excellent nanomaterials as drug delivery systems.

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The unique nanosized structures and biofunctions of BEVs are attractive for their use as nanomedicine platforms.

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BEVs have been investigated as biotherapeutics due to their loading capacity, ease of modification and industrialization.

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This review provides new insights of BEVs in drug delivery applications, discussing potential opportunities and challenges.

Loss of Bcl-3 delays bone fracture healing through activating NF-κB signaling in mesenchymal stem cells

Background

Bone fracture healing is a postnatal regenerative process in which fibrocartilaginous callus formation and bony callus formation are important. Bony callus formation requires osteoblastic differentiation of MSCs.

Materials and methods

The formation of callus was assessed by μCT, Safranin-O, H&E and Masson trichrome staining. Osteogenesis of MSCs was analyzed by ALP staining, ARS staining, qRT-PCR and WB. And we also used IF and TOP/FOP Flash luciferase reporter to assess the nuclear translocation of PP65.

Results

In this study, we found Bcl-3 showed a significant correlation with bone fracture healing. Results of μCT showed that loss of Bcl-3 delays bone fracture healing. Safranin-O, H&E and Masson trichrome staining confirmed that loss of Bcl-3 impacted the formation of cartilage and woven bone in callus. Further experiments in vitro manifested that Bcl-3-knockdown could inhibit MSCs osteoblastic differentiation through releasing the inhibition on NF-κB signaling by Co-IP, IF staining and luciferase reporter assay.

Conclusions

We unveiled that loss of Bcl-3 could lead to inhibited osteogenic differentiation of MSCs via promoting PP65 nuclear translocation.

The translational potential of this article

Our data demonstrated that overexpression of Bcl-3 accelerates bone fracture healing, which serves as a promising therapeutic target for bone fracture treatment.

LPS/Bcl3/YAP1 signaling promotes Sox9+HNF4α+ hepatocyte-mediated liver regeneration after hepatectomy

Recent reports have demonstrated that Sox9+HNF4α+ hepatocytes are involved in liver regeneration after chronic liver injury; however, little is known about the origin of Sox9+HNF4α+ hepatocytes and the regulatory mechanism. Employing a combination of chimeric lineage tracing, immunofluorescence, and immunohistochemistry, we demonstrate that Sox9+HNF4α+ hepatocytes, generated by transition from mature hepatocytes, play an important role in the initial phase after partial hepatectomy (PHx). Additionally, knocking down the expression of Sox9 suppresses hepatocyte proliferation and blocks the recovery of lost hepatic tissue. In vitro and in vivo assays demonstrated that Bcl3, activated by LPS, promotes hepatocyte conversion and liver regeneration. Mechanistically, Bcl3 forms a complex with and deubiquitinates YAP1 and further induces YAP1 to translocate into the nucleus, resulting in Sox9 upregulation and mature hepatocyte conversion. We demonstrate that Bcl3 promotes Sox9+HNF4α+ hepatocytes to participate in liver regeneration, and might therefore be a potential target for enhancing regeneration after liver injury.

Lipophilic Red-Emitting Carbon Dots for Detecting and Tracking Lipid Droplets in Live Cells

Lipid droplets (LDs), a dynamic organelle, are of vital importance in regulating the storage of neutral lipids and energy homeostasis. The aberrant expression of LDs is found to be highly associated with diverse metabolic diseases. Thus, detecting and monitoring LDs are essential to study the pathological and physiological processes of LDs in living bodies. However, it remains challenging to obtain suitable imaging probes to track LDs in vivo. Fortunately, the emergence of carbon dots (CDs), which are fluorescent nanomaterials with good biocompatibility and high stability, has provided us an unprecedented choice. In this work, CDs were synthesized via a solvothermal treatment of commercial reagents, 3-dimethylaminophenol. Interestingly, the prepared CDs show an intense red emission in non-hydrogen-bonding solution and have strong LD-targeting ability without any postmodification of ligands. Moreover, due to their low phototoxicity and excellent photostability, CDs were successfully applied to track the dynamics of LDs in live cells and image LDs in different cell lines and lipid-rich tissues. Overall, this work here proposed an LD-specific red-emitting CD probe, which will be of great value for learning more about LD-associated behaviors and diseases.

Bone Marrow Mesenchymal Stromal Cells: Identification, Classification, and Differentiation

Bone marrow mesenchymal stromal cells (BMSCs), identified as pericytes comprising the hematopoietic niche, are a group of heterogeneous cells composed of multipotent stem cells, including osteochondral and adipocyte progenitors. Nevertheless, the identification and classification are still controversial, which limits their application. In recent years, by lineage tracing and single-cell sequencing, several new subgroups of BMSCs and their roles in normal physiological and pathological conditions have been clarified. Key regulators and mechanisms controlling the fate of BMSCs are being revealed. Cross-talk among subgroups of bone marrow mesenchymal cells has been demonstrated. In this review, we focus on recent advances in the identification and classification of BMSCs, which provides important implications for clinical applications.

Corrigendum: Super-Resolution Microscopy: Shedding New Light on In Vivo Imaging

[This corrects the article DOI: 10.3389/fchem.2021.746900.].

Quantitatively mapping the interaction of HER2 and EGFR on cell membranes with peptide probes

Human epidermal growth factor receptor-2 (HER2) is a member of the epidermal growth factor receptor (HER) family that is involved in various biological processes such as cell proliferation, survival, differentiation, migration and invasion. It generally functions in the form of homo-/hetero-dimers or oligomers with other HER family members. Although its essential roles in cellular activities have been widely recognized, questions concerning the spatial distribution of HER2 on the membranes and the interactions between it and other ErbB family members remain obscure. Here, we obtained a high-quality dSTORM image of HER2 nanoscale clusters recognized by peptide probes, and found that HER2 forms clusters containing different numbers of molecules on cell membranes. Moreover, we found that HER2 and EGFR formed hetero-oligomers on non-stimulated cell membranes, whereas EGF stimulation reduced the degree of heteromerization, suggesting that HER2 and EGFR hetero-oligomers may inhibit the activation of EGFR. Collectively, our work revealed the clustered distribution of HER2 and quantified the changes of the interaction between HER2 and EGFR in the resting and active states at the single molecular level, which promotes a deeper understanding of the protein-protein interaction on cell membranes.

The hepatic senescence-associated secretory phenotype promotes hepatocarcinogenesis through Bcl3-dependent activation of macrophages

Background

Liver cancer is one of the most common malignancies in the world with a poor prognosis. Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer, accounting for 80–90% of cases. The initiation and progression of HCC are closely associated with chronic liver inflammation. In addition, HCC is often accompanied by cell senescence. Senescent hepatocytes can secrete various inflammatory factors, collectively called the senescence-associated secretory phenotype (SASP). The SASP has been confirmed to promote the occurrence of liver cancer by affecting the inflammatory microenvironment. However, its role and the underlying mechanism of hepatic SASP in hepatocarcinogenesis are not clearly understood. Therefore, a better understanding of the pathogenic mechanisms of the effect of the hepatic SASP on the occurrence of HCC is still needed.

Methods

The study aims to explore the role of SASP factors and the underlying mechanism in tumorigenesis and the progression of HCC in vivo. We used diethylnitrosamine (DEN) combined with carbon tetrachloride (CCl₄) (DEN-CCl₄) to establish liver cancer model in wild-type (WT) mice and Bcl3 knockout (Bcl3^−/−) mice. β-galactosidase (β-gal) staining was performed to evaluate the degree of cellular senescence. Immunohistochemistry (IHC) were used to detect the degree of cellular senescence and the activation of macrophage. PCR chip and clinical tissue chip assays were used to estimate the RNA levels of SASP factors and NF-κB related genes, and their protein levels were examined by Western blot assays.

Results

DEN-CCl₄ induced cellular senescence in mouse hepatocytes. In addition, senescent hepatocytes might release a variety of inflammatory factors that further activate macrophages, thereby changing the microenvironmental state and promoting the occurrence of HCC. Mechanistically, the NF-κB pathway is important because it regulates the SASP. Therefore, we used a PCR chip to detect the expression of NF-κB-related genes in senescent liver tissue. Our results showed that the expression of Bcl3 was increased in senescent hepatocytes, and knocking out Bcl3 significantly inhibited the secretion of hepatocyte SASP factors and the activation of macrophages, thereby inhibiting hepatocarcinogenesis. Finally, in clinical tissues adjacent to HCC tissues in patients, the expression of Bcl3 and IL-8 correlated with poor prognosis in HCC patients.

Conclusion

The hepatic SASP can further induce the activation of macrophages during hepatocarcinogenesis, thereby promoting the occurrence of HCC, and that this process is closely related to the expression of Bcl3 in hepatocytes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-021-00683-5.

Super-Resolution Microscopy: Shedding New Light on In Vivo Imaging

Over the past two decades, super-resolution microscopy (SRM), which offered a significant improvement in resolution over conventional light microscopy, has become a powerful tool to visualize biological activities in both fixed and living cells. However, completely understanding biological processes requires studying cells in a physiological context at high spatiotemporal resolution. Recently, SRM has showcased its ability to observe the detailed structures and dynamics in living species. Here we summarized recent technical advancements in SRM that have been successfully applied to in vivo imaging. Then, improvements in the labeling strategies are discussed together with the spectroscopic and chemical demands of the fluorophores. Finally, we broadly reviewed the current applications for super-resolution techniques in living species and highlighted some inherent challenges faced in this emerging field. We hope that this review could serve as an ideal reference for researchers as well as beginners in the relevant field of in vivo super resolution imaging.

The stemness of hepatocytes is maintained by high levels of lipopolysaccharide via YAP1 activation

Background

The liver possesses a powerful regeneration ability, which is correlated with the stemness of hepatocytes in the portal vein (PV). However, the mechanism underlying the maintenance of hepatocyte stemness has not been elucidated. Here, we hypothesized that high levels of lipopolysaccharide from the portal vein might maintain the stemness of hepatocytes in the PV area.

Methods

First, we examined the location of hepatic stem cells and the concentration of lipopolysaccharide (LPS) in the portal vein and inferior vena cava. Then, we assessed the effect of LPS on stemness maintenance in mice by using antibiotics to eliminate LPS and knocking out the LPS receptor, TLR4. In vitro, the effect of LPS on the stemness of hepatocytes was investigated by colony and sphere formation assays and assessment of pluripotent and stem cell marker expression. Furthermore, we studied the mechanism by which LPS regulates the stemness of hepatocytes. Finally, we ligated the portal vein branch to further verify the effect of LPS.

Results

We found that a high level of LPS from the portal vein was correlated with the location of hepatic stem cells in the PV area, and elimination of LPS by antibiotics inhibited the expression of the stemness marker. LPS promoted colony and sphere formation and induced the upregulation of pluripotent and stem cell markers in AML12 cells. Furthermore, in the reprogramming medium, LPS facilitated the dedifferentiation of mature hepatocytes into hepatic progenitor-like cells, which exhibited a bipotent differentiation capacity in vivo and in vitro. Mechanistically, LPS bound TLR4 to regulate stemness of hepatocytes via the activation of YAP1 signaling, and blockade of YAP1 abolished the LPS-induced cell stemness and upregulation of pluripotent markers.

Conclusions

Our study implies a correlation between LPS/TLR4/YAP1 signaling and cell stemness, and LPS was shown to be involved in stemness maintenance of hepatocytes in the PV area. LPS might be used to induce the dedifferentiation of mature hepatocytes into progenitor-like cells for repair of liver injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02421-7.

Autophagy deficiency downregulates O6methylguanine-DNA methyltransferase and increases chemosensitivity of liver cancer cells

It is known that autophagy-deficient cells are prone to DNA damage, but the specific role of autophagy in DNA damage repair is not fully known. Here, we show that autophagy-deficient liver cancer cells exhibit increased DNA damage caused by the chemotherapeutic agent epirubicin. Autophagy deficiency promotes downregulation of the DNA repair enzyme O⁶methylguanine-DNA methyltransferase (MGMT) in liver cancer cells. However, autophagy induction with epirubicin had no impact on MGMT gene or protein expression in liver cancer cells. In the absence of autophagy, the chemosensitivity of liver cancer cells was increased, but this was reversed by MGMT overexpression, indicating that autophagy mediates resistance to chemotherapy in liver cancer cells via MGMT. These findings demonstrate a direct link between autophagy, MGMT, and DNA damage repair in liver cancer cells, and show that MGMT not only regulates chemosensitivity to alkylating agents, but may also be involved in other DNA damage repair processes in autophagy-deficient cells.

Autophagy Is Required for Hepatic Differentiation of Hepatic Progenitor Cells via Wnt Signaling Pathway

The molecular mechanisms regulating differentiation of hepatic progenitor cells (HPCs), which play pivotal roles in liver regeneration and development, remain obscure. Autophagy and Wnt signaling pathways regulate the development and differentiation of stem cells in various organs. However, the roles of autophagy and Wnt signaling pathways in hepatic differentiation of HPCs are not well understood. Here, we describe the effects of autophagy and Wnt signaling pathways during hepatic differentiation of HPCs. We used a well-established rat hepatic progenitor cell line called WB-F344, which was treated with differentiation medium to promote differentiation of WB-F344 cells along the hepatic phenotype. Firstly, autophagy was highly activated in HPCs and gradually decreased during hepatic differentiation of HPCs. Induction of autophagy by rapamycin or starvation suppressed hepatic differentiation of HPCs. Secondly, Wnt3a signaling pathway was downregulated, and Wnt5a signaling pathway was upregulated in hepatic differentiation of HPCs. At last, Wnt3a signaling pathway was enhanced, and Wnt5a signaling pathway was inhibited by activation of autophagy during hepatic differentiation of HPCs. In summary, these results demonstrate that autophagy regulates hepatic differentiation of hepatic progenitor cells through Wnt signaling pathway.

The role of CD47-SIRPα immune checkpoint in tumor immune evasion and innate immunotherapy

As a transmembrane protein, CD47 plays an important role in mediating cell proliferation, migration, phagocytosis, apoptosis, immune homeostasis, inhibition of NO signal transduction and other related reactions. Upon the interaction of innate immune checkpoint CD47-SIRPα occurrence, they send a "don't eat me" signal to the macrophages. This signal ultimately helps tumors achieve immune escape by inhibiting macrophage contraction to prevent tumor cells from phagocytosis. Therefore, the importance of CD47-SIRPα immune checkpoint inhibitors in tumor immunotherapy has attracted more attention in recent years. Based on the cognitive improvement of the effect with CD47 in tumor microenvironment and tumor characteristics, the pace of tumor treatment strategies for CD47-SIRPα immune checkpoint inhibitors has gradually accelerated. In this review, we introduced the high expression of CD47 in cancer cells to avoid phagocytosis by immune cells and the importance of CD47 in the structure of cancer microenvironment and the maintenance of cancer cell characteristics. Given the role of the innate immune system in tumorigenesis and development, an improved understanding of the anti-tumor process of innate immune checkpoint inhibitors can lay the foundation for more effective combinations with other anti-tumor treatment strategies.

Exosome-guided bone targeted delivery of Antagomir-188 as an anabolic therapy for bone loss

The differentiation shift from osteogenesis to adipogenesis of bone marrow mesenchymal stem cells (BMSCs) characterizes many pathological bone loss conditions. Stromal cell-derived factor-1 (SDF1) is highly enriched in the bone marrow for C-X-C motif chemokine receptor 4 (CXCR4)-positive hematopoietic stem cell (HSC) homing and tumor bone metastasis. In this study, we displayed CXCR4 on the surface of exosomes derived from genetically engineered NIH-3T3 cells. CXCR4⁺ exosomes selectively accumulated in the bone marrow. Then, we fused CXCR4⁺ exosomes with liposomes carrying antagomir-188 to produce hybrid nanoparticles (NPs). The hybrid NPs specifically gathered in the bone marrow and released antagomir-188, which promoted osteogenesis and inhibited adipogenesis of BMSCs and thereby reversed age-related trabecular bone loss and decreased cortical bone porosity in mice. Taken together, this study presents a novel way to obtain bone-targeted exosomes via surface display of CXCR4 and a promising anabolic therapeutic approach for age-related bone loss.

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Surface display of CXCR4 grants exosomes bone targeting properties.

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Exosome-liposome hybrid nanoparticles carrying nucleic acid target bone.

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Antagomir-188 loaded hybrid nanoparticles regulate MSC differentiation in aged mice.

Mechanistic Insights into Trop2 Clustering on Lung Cancer Cell Membranes Revealed by Super-resolution Imaging

The transmembrane glycoprotein Trop2 plays important roles in various types of human cancers, especially lung cancer. Although it has been found to form clusters on cancer cell membranes, the factors that affect its clustering are not yet fully understood. Here, using direct stochastic optical reconstruction microscopy (dSTORM), we found that Trop2 generated more, larger, and denser clusters on apical cell membranes than on basal membranes and that the differences might be related to the different membrane structures. Moreover, dual-color dSTORM imaging revealed significant colocalization of Trop2 and lipid rafts, and methyl-β-cyclodextrin disruption dramatically impaired the formation of Trop2 clusters, indicating a key role of lipid rafts in Trop2 clustering. Additionally, depolymerization of the actin cytoskeleton decreased Trop2 cluster numbers and areas, revealing that actin can stabilize the clusters. More importantly, stimulation of Trop2 in cancer cells hardly changed the cluster morphology, suggesting that Trop2 is activated and forms clusters in cancer cells. Altogether, our work links the spatial organization of Trop2 to different membrane structures and Trop activation and uncovers the essential roles of lipid rafts and actin in Trop2 cluster maintenance.

Application of an inhibitor-based probe to reveal the distribution of membrane PSMA in dSTORM imaging

Relying on an inhibitor-based probe, we reveal the clustered distribution of membrane PSMA by dSTORM imaging and uncover its potential interaction with folate receptor. This inhibitor-based strategy realizes more accurate labeling than antibody labeling, which would make it a powerful tool in the field of dSTORM imaging.

Mesenchymal stem cells promote chemoresistance by activating autophagy in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is a type of cancer that is difficult to cure; chemoresistance of cholangiocarcinoma cells affect the prognosis of patients who cannot be treated with surgery. The mechanism underlying this chemoresistance remains unknown. Mesenchymal stem cells (MSCs) are known to be important components of the tumor microenvironment. In the present study, a large number of MSCs were observed to infiltrate the tumor sites of ICC; thus, MSCs were isolated from ICC tumor tissues. It was revealed that herpesvirus entry mediator (HVEM) was overexpressed in ICC‑MSCs. The present study then investigated the role of HVEM‑overexpressing MSCs in the chemoresistance of cholangiocarcinoma cells. It was demonstrated that HVEM‑overexpressing MSCs could support cell survival of chemotherapeutic cholangiocarcinoma cells and inhibited their apoptosis. Further investigations revealed that HVEM‑overexpressing MSCs could secrete IL‑6 and also activated AMPK/mTOR‑dependent autophagy of cholangiocarcinoma cells. Thus, it was concluded that ICC‑MSC‑induced autophagy is the primary cause of chemoresistance in ICC.

Development of small molecule inhibitor-based fluorescent probes for highly specific super-resolution imaging

To ensure the ultimate high-quality imaging of super-resolution fluorescence microscopy with increasingly high resolution, it is significant to use small specific fluorescent probes. Compared with the common biological fluorescent labeling technology, because of small size, strong specificity, abundance and special binding sites, single-targeted small-molecule inhibitors (SMIs) can link with organic dyes to form small fluorescent probes for various biomolecules. Herein, to confirm the feasibility of the SMI-probes, epidermal growth factor (EGF) receptor (EGFR)-targeted tyrosine kinase inhibitor Gefitinib was selected for modification with the fluorescent dye to form Gefitinib-probe. Then, the labeling superiority of Gefitinib-probe was revealed by comparing the direct stochastic optical reconstruction microscopy (dSTORM) images of EGFR labeled with different probes. Additionally, a high co-localization of fluorescent points from Gefitinib-probe and EGF-probe labeling indicated a high specificity of Gefitinib-probe to EGFR. Finally, higher co-localization of EGFR and HER3 labeled with the probe pair containing Gefitinib-probe than with the antibody-probe pair suggested that Gefitinib-probe with a cytoplasmic binding site benefited dual-color imaging. These results indicate that the SMI-probes are able to serve as versatile labeling tools for high-quality super-resolution imaging.

Aptamer AS1411 utilized for super-resolution imaging of nucleolin

Nucleolin (NCL) is a multifunctional protein that mainly localizes in the nucleolus and also distributes in the nucleoplasm, cytoplasm and cell membrane. Most studies focus on its biofunctions in cell activities and diseases, however, its detailed distribution and organization pattern in situ remains obscure. Moreover, antibodies were commonly used to investigate NCL in cells. It is worth noting that antibody labeling of intracellular proteins needs detergents to permeabilize the membrane, which could disrupt the membrane structure and proteins. The emergence of aptamer AS1411 provides us a good choice to recognize the NCL without permeabilization owing to its superior cellular uptake and enhanced stability. Therefore, we applied aptamer AS1411 to super-resolution imaging to visualize the distribution of NCL at a nanometer level. Aptamer achieved a better recognition of intracellular NCL and displayed the detailed structure of NCL in different parts of cells. Significantly, cytoplasmic and membrane NCL have higher expression and larger clusters in cancer cells than that in normal cells. Our work presented a detailed organization of NCL in cells and revealed the distribution differences between cancer cells and normal cells, which promote the understanding of its functions in physiology and pathology.

Correlative dual-color dSTORM/AFM reveals protein clusters at the cytoplasmic side of human bronchial epithelium membranes

The organization of a cell membrane is vital for various functions, such as receptor signaling and membrane traffic. However, the understanding of membrane organization remains insufficient, especially the localizations of specific proteins in the cell membrane. Here, we used correlative super-resolution fluorescence/atomic force microscopy to correlate the distributions of specific proteins Na+/K+-ATPase (NKA, an integral membrane protein) and ankyrin G (AnkG, a scaffolding protein) with the topography of the cytoplasmic side of human bronchial epithelium membranes. Our data showed that NKA and AnkG proteins preferred to localize in the protein islands of membranes. Interestingly, we also found that functional domains composed of specific proteins with a few hundreds of nanometers were formed by assembling protein islands with a few tens of nanometers.

Developing substrate-based small molecule fluorescent probes for super-resolution fluorescent imaging of various membrane transporters

Super-resolution imaging technology has been a powerful tool for revealing fine biological structures and functions. Its high-quality imaging always needs highly accurate labeling. Here, by exploiting the high specificity and affinity of natural substrates to transporters, we developed one set of substrate-based small molecule fluorescent probes for labeling membrane transporters. A glucose-based probe (Glu-probe) and tyrosine-based probe (Tyr-probe) were synthesized as two examples. Confocal imaging showed that the Glu-probe could label glucose transporters on live cells by being stuck into the binding site. Compared with antibody-probe labeling, the labeling advantages of the Glu-probe were revealed. High specificity of the Glu-probe or Tyr-probe was examined by a colocalization experiment and glucose replacement or amino acid (AA) blocking. The synthetic probes were also tested on imaging HeLa cells to confirm their wide labeling application. Additionally, we found that membrane transporters were mostly in the clustered state on cellular membranes, changing their assembly pattern to regulate the transport effectiveness. These results suggest that the substrate-based probes can serve as valuable tools for investigating the spatial information of membrane transporters.

Mechanical force regulation of YAP by F-actin and GPCR revealed by super-resolution imaging

The Hippo signaling pathway plays critical roles in many biological processes including mechanotransduction. The key activator YAP of this pathway is considered as a central component of mechanotransduction signaling sensing the extracellular mechanical microenvironment changes, such as different cell density, the architecture of tissues and matrix stiffness. Although it has been largely studied that YAP is involved in these processes, the underlying mechanism of mechanical force-induced YAP regulation remains unclear. Here we exerted pressure on cell surfaces and investigated how YAP senses the extracellular mechanical force change using one of the super-resolution imaging techniques, dSTORM. We demonstrated that pressure promoted F-actin depolymerization, RhoA down-regulation, and LPAR1 (Gα12/13-coupled receptor) inactivation, which led to YAP cytoplasmic translocation and decreased clustering. Our work uncovers the role of GPCRs and F-actin in pressure-controlled YAP inactivation, and provides new insights into the mechanisms of mechanical regulation of the Hippo signaling pathway.

The concentration of tumor necrosis factor-α determines its protective or damaging effect on liver injury by regulating Yap activity

Previous studies have shown that tumor necrosis factor (TNF)-α is a mediator of hepatotoxicity in liver injury. Moreover, TNF-α has also been reported to have a protective effect in liver regeneration, yet the function of TNF-α during liver injury remains controversial. Here, we report that the concentration of TNF-α determines its functions. High concentrations of TNF-α could aggravate LPS-induced liver injury. However, the TNF-α level was unchanged during APAP-induced liver injury, which exerted a protective effect. We expected that the concentration of TNF-α may affect its function. To test this hypothesis, TNF-α^−/− rats or hepatocyte cells were treated with different concentrations of TNF-α. We found low TNF-α could reduce the levels of ALT and AST in the plasma of TNF-α^−/− rats and promote the proliferation of hepatocyte cells. However, the levels of ALT and AST increased gradually with increasing TNF-α concentration after reaching the lowest value. Moreover, we showed that TNF-α affects the cell proliferation and cell death of hepatocytes by regulating Yap activity. Low TNF-α promoted Yap1 nuclear translocation, triggering the proliferation of hepatocytes. However, high TNF-α triggered the phosphorylation and inactivation of Yap1, preventing its nuclear import and consequently promoting cell death. Collectively, our findings provide novel evidence that the concentration of TNF-α is an important factor affecting its function in liver injury, which may provide a reference for the clinical treatment of liver injury.

Autophagy and Tumour Stem Cells

Autophagy is critical for the survival and stemness maintenance of cancer stem cells (CSCs) and is an enhancer of CSC tumorigenesis. At the same time, autophagy contributes to conditions optimal for facilitating the invasion and metastasis of CSCs. Moreover, autophagy induces the dormant state of CSCs to help them resist the cytotoxic effects of chemotherapy and radiotherapy, thereby improving the likelihood of their survival. The combination of autophagy inhibitors with specific drugs targeting specific CSC subpopulations is expected to act specifically on CSCs and produce fewer toxic side effects on normal tissues. This in-depth study is very timely and important for further identifying the potential role of autophagy in different states of CSCs and places a particular emphasis on exploring molecular mechanisms in the regulation of autophagy via advanced techniques based on molecular biology.

Variation of Trop2 on non-small-cell lung cancer and normal cell membranes revealed by super-resolution fluorescence imaging

Transmembrane glycoprotein Trop2 is related to many epithelial carcinomas. It not only plays roles in promoting fetal lung growth but also participates in tumor genesis, malignant transformation, and tumor dissemination. However, the detailed distribution of Trop2 at the molecular level remains unknown. Herein, we used direct stochastic optical reconstruction microscopy to reveal the spatial organization of Trop2 on the membranes of cultured and primary lung cancer cells and normal cells. All types of cancer cells presented more localizations of Trop2 than normal cells. By SR-Teseller cluster analysis, we found that Trop2 existed in the form of clusters on all the membranes; however, cancer cells generated more and larger clusters consisting of more molecules than normal cells. Our findings shed light on the heterogeneous distribution of membrane Trop2 and highlighted the significant differences of its clustering characteristics between lung cancer cells and normal cells, which laid the basis for further studying the mechanism and functions of Trop2 clustering in lung cancer.

Super-resolution imaging of cancer-associated carbohydrates using aptamer probes

Globo H, as one of the most crucial cancer-associated carbohydrates, is exclusively overexpressed in a variety of cancers. However, the accurate localization and detailed morphology of globo H at the molecular level remain unclear. Here, we applied direct stochastic optical reconstruction microscopy (dSTORM) and relied on fluorophore-conjugated aptamers to solve the problem. The results showed that globo H organized as clusters on cell membranes with irregular shapes and different sizes from 100 to 300 nm. Significantly, globo H was found to have a higher expression level and larger clusters on various cancer cells than on non-cancer cells, which hinted that its specific distribution could be utilized for cancer diagnosis. Moreover, dual-color dSTORM imaging revealed the colocalization of globo H and other cancer-associated carbohydrates, and the clustering of globo H could be disrupted by the treatment of corresponding glycosidases, which indicated that these carbohydrates might intertwine in spatial organization and function cooperatively in cancers. Our work clarified the clustered distribution of globo H at the nanometer scale and revealed the potential interactions between cancer-associated carbohydrates, which paves the way for further understanding the relationship between the spatial structures and functions of carbohydrates in cancers.

[Correlation analysis of incidence, season and temperature parameters of different types of sudden deafness]

Objective:The objective of this study was to investigate the correlation between the onset of different types of sudden sensorineural hearing loss（SSNHL） with temperature parameters and seasons. Method:We retrospectively reviewed the medical charts of 175 patients who were diagnosed as SSNHL, precisely collected the exact date and city of onset, confirmed the season, and obtained the meteorological data including maximum temperature（Tmax）, minimum temperature（Tmin）, mean temperature（T）, day-to-day change of mean temperature（ΔT）, and diurnal temperature range（Trange） at the same day, then analyzed the relation between season and temperature with the onset of different types of SSNHL. Result:There was a significant difference of Trange between different types of SSNHL（P=0.001）. Trange on the onset date of all-frequency SSNHL（including flat and profound type） was significantly higher than low and high frequency descending type（P=0.001, P<0.05 respectively）. Types of SSNHL had weak association with Trange groups（P=0.03, Cramer's V=0.220）. An increase of 1℃ in Trange increased the risk of flat type SSNHL by 23.9% and 16.5% compared with low and high frequency descending type, respectively, and for profound type, the risk was increased by 22.4% and 15.1%. No significant differences were observed between seasons and SSNHL types（P=0.666）. Conclusion:The incidence of different types of sudden sputum may be related to the worse temperature on the day, and has nothing to do with the disease season.

[The correlation between plasma fibrinogen level and different types of sudden sensorineural hearing loss]

Objective: To investigate the correlation between plasma fibrinogen level and the incidence of sudden hearing loss. Method: A total of 225 patients (age ranging from 18 to 70 years) with sudden sensorineural hearing loss(SSNHL) were selected. The disease onset was within 2 weeks. No patient received previous medical intervention. Depending on the types of auditory threshold curve, SSNHL was divided into low frequency descending type, high frequency descending type, flat desending type and total deafness type. Two hundred and twenty-nine cases with normal hearing and no inflammatory diseases in the same period was selected as control group. Fibrinogen level and Blood Routine Indexes were detected for the purpose of retrospective cohort study.Result: The levels of fibrinogen in SSNHL group(2.98±0.59) g/L were significantly higher than that in control group(2.66±0.36) g/L (P<0.01). According to the types of auditory threshold curve, SSNHL groups were divided into group A(55 cases, 24.44%), Group B(36 cases, 16.00%), Group C(43 cases,19.11%) and Group D(91 cases, 40.44%). The average fibrinogen levels before treatment were at(2.75±0.46)g/L, (3.16±0.61) g/L, (3.02±0.63) g/L and(3.03±0.63) g/L respectively. There was no significant difference in fibrinogen level(P=0.286) between group A and the control group. Fibrinogen levels of group B, group C and group D were significantly elevated compared to control group (P<0.01). Conclusion: The level of fibrinogen is not significantly correlated with development of sudden deafness of low frequency descending type. The incidence of high frequency descending type, flat descending type and profound deafness type are all correlated with the level of high fibrinogen at the onset of sudden deafness. The classification of sudden deafness based on audiogram curves could be of great significance for analysis of possible causes and selection of treatment options.

Lipopolysaccharide protects against acetaminophen-induced hepatotoxicity by reducing oxidative stress via the TNF-α/TNFR1 pathway

Robust evidence suggested that gut-derived lipopolysaccharide (LPS) plays a significant role in various liver injury diseases; however, the role of gut-derived LPS in acetaminophen (APAP) overdose-induced acute liver injury remains unclear. The present study aimed to investigate the effect of gut-derived LPS on APAP-induced liver injury. Our results revealed that reduction of gut-derived LPS using multiple antibiotics could significantly exacerbate APAP-induced liver injury and increase mortality in mice. By contrast, pretreatment with exogenous LPS could reverse APAP-induced liver hepatotoxicity in mice and rats. We observed that TNF-α secretion in the liver was significantly increased after LPS pretreatment. In addition, depletion of TNF-α or TNFR1 inhibited the protective effects of LPS against APAP-induced hepatotoxicity, which indicated that the TNF-α/TNFR1 pathway was required to protect against APAP-induced liver injury. Mechanistically, LPS reduces oxidative stress by upregulating the expression of hepatic GSH, reducing MDA levels in liver tissues, and upregulating the expression of several antioxidant genes after APAP injection. However, the production of hepatic GSH was not enhanced in the liver tissues of rats lacking TNF-α or TNFR1 and MDA levels were not reduced after LPS and APAP co-treatment. The above results suggested LPS alleviated APAP-induced oxidative stress via the TNF-α/TNFR1 pathway.

[Study on the relationship between age-related hearing loss and cognitive impairment]

Objective: To investigate the correlation between age-related hearing loss and cognitive impairment. Methods: 201 elderly patients, who were admitted to the Department of Otorhinolaryngology of Peking University People's Hospital from March 1, 2017 to March 31, 2017, were evaluated with hearing screening and the Montreal Cognitive Assessment Scale. Among them, 101 were female and 100 were male, aged 60-90 years old. Taking the cognitive level as the dependent variable, and taking the age, sex, education, occupation, marital status, residence, and average hearing loss (average hearing threshold of 500, 1 000, 2 000, and 4 000 Hz), as well as the length of conscious hearing loss as the independent variables, the single factor analysis and multivariate linear regression analysis were used to screen the main factors affecting the cognitive level of the elderly. Results: Of the 201 elderly patients, 39 had normal hearing, 65 had mild hearing loss, 80 had moderate hearing loss, 16 had severe hearing loss, and 1 had profound hearing loss. The average degree of hearing loss was the influencing factor of cognitive impairment, and it mainly affected the directional force and abstract ability in the cognitive domains (P<0.05); The age, self-reported hearing loss, years of education, marital status, past ear diseases, and hypertension were relatively independent factors that affected the cognitive level(P<0.05). Conclusions: Age-related hearing loss is the risk factor for the cognitive impairment, especially for abstraction and orientation, in the elderly. The self-reported hearing loss is an independent risk factor for cognitive impairment.

[Study on the effects of microRNA-203 on the invasion and apoptosis of laryngeal cancer cells via targeting LASP1]

Objective: To explore the role of microRNA-203 in laryngeal cancer and its underlying mechanism and clarify the relationship between microRNA-203 and LASP1.Method: microRNA-203 expression in laryngeal cancer tissues and paracancerous tissues was detected by quantitative real time-polymerase chain reaction（qRT-PCR）. The regulatory effects of microRNA-203 on invasion and apoptosis of laryngeal cancer cells were detected by Transwell assay and flow cytometry, respectively. Dual-luciferase reporter gene assay was performed to access the binding condition of microRNA-203 and LASP1. Both mRNA and protein levels of LASP1 in laryngeal cancer cells were detected after transfection with microRNA-203 mimic or microRNA-203 inhibitor by qRT-PCR and Western blot. Rescue experiments were finally performed to detect whether microRNA-203 regulates laryngeal cancer development via targeting LASP1. Result: microRNA-203 was lowly expressed in laryngeal cancer tissues and cell lines.Knockdown of microRNA-203 in Hep-2 cells can promote the invasiveness and inhibit apoptosis of laryngeal cancer cells. Subsequently,LASP1 was predicted to be the target gene of microRNA-203，which was further verified by dual-luciferase reporter gene assay.LASP1 expression was negatively regulated by microRNA-203. Furthermore，rescue experiments showed that microRNA-203 regulates invasion and apoptosis of laryngeal cancer cells via targeting LASP1. Conclusion： Low expression of microRNA-203 could promote the invasion and inhibit apoptosis of laryngeal cancer cells viainhibiting LASP1. microRNA-203 and LASP1 both play a very important role in the development of laryngeal cancer..