SOX2 regulates paclitaxel resistance of A549 non­small cell lung cancer cells via promoting transcription of ClC­3.

Paclitaxel (PTX) is widely used in the treatment of non­small cell lung cancer (NSCLC). However, acquired PTX drug resistance is a major obstacle to its therapeutic efficacy and the underlying mechanisms are still unclear. The present study revealed a novel role of the SRY­box transcription factor 2 (SOX2)­chloride voltage­gated channel­3 (ClC­3) axis in PTX resistance of A549 NSCLC cells. The expression levels of SOX2 and ClC­3 were upregulated in PTX­resistant A549 NSCLC cells by RT­qPCR and western blotting. The drug resistance to PTX of A549 NSCLC cells were measured by detecting the cell viability and the expression of drug resistance markers. Knockdown of SOX2 or ClC­3 effectively decreased PTX resistance of A549 NSCLC cells, whereas SOX2 or ClC­3 overexpression promoted PTX resistance. Mechanistically, SOX2 bound to the promoter of ClC­3 and enhanced the transcriptional activation of ClC­3 expression by CUT&Tag assays, CUT&Tag qPCR and luciferase reporter. In summary, the present findings defined ClC­3 as an important downstream effector of SOX2 and ClC­3 and SOX2 contributed to PTX resistance. Targeting SOX2 and its downstream effector ClC­3 increased the sensitivity of NSCLC cells to PTX treatment, which provided potential therapeutic strategies for patients with NSCLC with PTX resistance.

Correlated States in Strained Twisted Bilayer Graphenes Away from the Magic Angle.

Graphene moiré superlattice formed by rotating two graphene sheets can host strongly correlated and topological states when flat bands form at so-called magic angles. Here, we report that, for a twisting angle far away from the magic angle, the heterostrain induced during stacking heterostructures can also create flat bands. Combining a direct visualization of strain effect in twisted bilayer graphene moiré superlattices and transport measurements, features of correlated states appear at "non-magic" angles in twisted bilayer graphene under the heterostrain. Observing correlated states in these "non-standard" conditions can enrich the understanding of the possible origins of the correlated states and widen the freedom in tuning the moiré heterostructures and the scope of exploring the correlated physics in moiré superlattices.

FoxO1 suppresses IL-10 producing B cell differentiation via negatively regulating Blimp-1 expression and contributes to allergic asthma progression.

IL-10-producing B cells (B10) are involved in the prevention of autoimmune and allergic responses but its mechanisms remain poorly understood. We took advantage of the ovalbumin-induced asthma mouse model to demonstrate that the activity of FoxO1 is upregulated in lung B cells and correlates inversely with B10 cells, while showing decreased activity in ex vivo and in vitro induced B10 cells. We further observed that FoxO1 deficiency leads to increased frequency of B10 cells. These observations have in vivo clinical evidence, as B cell specific FoxO1 deficiency leads to reduced lung eosinophils and asthma remission in mice, and there are reduced regulatory B cells and increased FoxO1 activity in B cells of asthma patients. Single cell RNA-sequencing data demonstrated a negative correlation between the expression of Foxo1 and Il10 in B cells from the mouse spleen and lung and the human lung. For a biological mechanism, FoxO1 inhibits the expression of Prdm1, which encodes Blimp-1, a transcription factor of B10 cells. Our experimental evidence in both murine and human asthma demonstrates that FoxO1 is a negative regulator of B10 cell differentiation via negatively regulating Prdm1 and its expression in B cells contributes to allergic asthma disease.

Chromatin accessibility analysis identifies the transcription factor ETV5 as a suppressor of adipose tissue macrophage activation in obesity.

Activation of adipose tissue macrophages (ATMs) contributes to chronic inflammation and insulin resistance in obesity. However, the transcriptional regulatory machinery involved in ATM activation during the development of obesity is not fully understood. Here, we profiled the chromatin accessibility of blood monocytes and ATMs from obese and lean mice using assay for transposase-accessible chromatin sequencing (ATAC-seq). We found that monocytes and ATMs from obese and lean mice exhibited distinct chromatin accessibility status. There are distinct regulatory elements that are specifically associated with monocyte or ATM activation in obesity. We also discovered several transcription factors that may regulate monocyte and ATM activation in obese mice, specifically a predicted transcription factor named ETS translocation variant 5 (ETV5). The expression of ETV5 was significantly decreased in ATMs from obese mice and its downregulation was mediated by palmitate stimulation. The decrease in ETV5 expression resulted in macrophage activation. Our results also indicate that ETV5 suppresses endoplasmic reticulum (ER) stress and Il6 expression in macrophages. Our work delineates the changes in chromatin accessibility in monocytes and ATMs during obesity, and identifies ETV5 as a critical transcription factor suppressing ATM activation, suggesting its potential use as a therapeutic target in obesity-related chronic inflammation.

ClC-3 chloride channel protein induces G1 arrest in hepatocellular carcinoma Hep3B cells.

ClC-3 is a type of chloride channel that has multiple functions in tumorigenesis and tumor growth, and can be blocked by DIDS (4,4'-diisothiocyanostilbene-2,2'-disulfonic acid). In the present study, we found that DIDS inhibited the proliferation of Hep3B hepatocellular carcinoma (HCC) cells in a concentration-dependent manner. More in-depth research demonstrated that DIDS downregulated the protein expression levels of cyclin D1 and cyclin E, which are key proteins of the G1 phase. Additionally, we found that ClC-3 siRNA transfection induced G1 arrest in the Hep3B cells, confirming that ClC-3 is involved in the DIDS-induced inhibition of Hep3B cells. Moreover, the level of α-fetoprotein (AFP), a negative prognostic indicator of HCC, was decreased after treatment with DIDS and ClC-3 siRNA. In conclusion, we demonstrated that ClC-3 can arrest the cell cycle at the G1 phase to inhibit cell proliferation, suggesting that ClC-3 has the potential to be a novel target for HCC therapy and potentially improve the prognosis of HCC patients.

A novel method of neural differentiation of PC12 cells by using Opti-MEM as a basic induction medium.

The PC12 cell line is a classical neuronal cell model due to its ability to acquire the sympathetic neurons features when deal with nerve growth factor (NGF). In the present study, the authors used a variety of different methods to induce PC12 cells, such as Opti-MEM medium containing different concentrations of fetal bovine serum (FBS) and horse serum compared with RPMI-1640 medium, and then observed the neurite length, differentiation, adhesion, cell proliferation and action potential, as well as the protein levels of axonal growth-associated protein 43 (GAP-43) and synaptic protein synapsin-1, among other differences. Compared with the conventional RPMI-1640 medium induction method, the new approach significantly improved the neurite length of induced cells (2.7 times longer), differentiation rate (30% increase), adhesion rate (21% increase) and expression of GAP-43 and synapsin-1 (three times), as well as reduced cell proliferation. The morphology of induced cells in Opti-MEM medium containing 0.5% FBS was more like that of neurons. Additionally, induced cells were also able to motivate the action potential after treatment for 6 days. Therefore, the research provided a novel, improved induction method of neural differentiation of PC12 cells using Opti-MEM medium containing 0.5% FBS, resulting in a better neuronal model cell line that can be widely used in neurobiology and neuropharmacology research.

A novel Nogo-66 receptor antagonist peptide promotes neurite regeneration in vitro.

The Nogo-66 receptor (NgR1), a receptor for Nogo-A, contributes to the inhibition of axonal regeneration in the adult central nervous system after traumatic injuries. Thus, NgR1 has been considered a critical target in axon regeneration therapy. Here, we identified a specific NgR1 antagonist peptide (HIYTALV, named NAP2) which promotes neurite regeneration in vitro from a phage display heptapeptide library. NAP2 was co-localized with NgR1 on the surface of PC12 cells and cerebellar granule cells (CGCs) by immunofluorescence assay. Horseradish peroxidase (HRP)-streptavidin-biotin assay further showed that NAP2 binds to NgR1 and the dissociation constant (Kd) was 0.45 µM Functional analyses indicated that NAP2 could reduce the inhibitory effects of Nogo-66 on neurite outgrowth in differentiated PC12 cells and CGCs by blocking the Nogo-66-induced activation of Rho-associated coiled coil-containing protein kinase (ROCK), collapsin response mediator protein 2 (CRMP2) and myosin light chain (MLC). Taken together, the small molecule NgR1 antagonist peptide NAP2 (MW: 815.98Da) has a potential ability in crossing blood brain barrier and will be a promising therapeutic agent for the treatment of spinal cord injury and neurodegenerative diseases.