[Evaluation of a modified maxillary protraction appliance for the treatment of patients with skeletal Class â ¢ malocclusion associated with crowding].

PURPOSE: To investigate the efficacy of a modified maxillary protraction appliance in patients of skeletal Class Ⅲ with crowding. METHODS: Forty patients with skeletal Class Ⅲ malocclusion were divided into two groups, with 20 patients in each group. The experimental group had molar in a neutral or distal relationship and applied a modified maxillary protraction appliance, while the control group had molar mesial relationship and applied a conventional maxillary protraction appliance. Lateral cephalometric radiographs were taken before and after treatment in both groups for comparison. SPSS 22.0 software package was used for data analysis. RESULTS: The angle measurements taken before and after treatment showed a significant increase in SNA, ANB, SN-MP and U4-SN(P＜0.01), while SNB decreased(P＜0.01) in both groups. SN-OL changes were statistically different before and after treatment in the experimental group(P＜0.05). The sagittal measurements before and after treatment in both groups showed significant alterations in all(P＜0.05) but the length of the maxillary arch in both groups. For vertical measurements, U1-PP, L1-MP, U4-SN, U6-SN, and ANS-ME all increased (P＜0.05), while the changes of U4-PP and U6-PP in the two groups before and after treatment were statistically different(P＜0.05). Compared with the control group, the experimental group had a significantly increased maxillary arch length, a more remote location at U6, and a less variable molar relationship after treatment(P＜0.01). The two groups showed a variable amount of cephalometric measurements before and after treatment: the experimental group had a significant increase in maxillary arch length, a more remote position at U6, and a smaller change in molar relationship compared to the control group(P＜0.01). CONCLUSIONS: The modified maxillary protraction appliance showed good results for maxillary protraction and pushing the molar distally in patients with skeletal Class Ⅲ with crowding at neutral or distal molar relationship.

Reconstructive strategies following surgical resection of malignant sublingual gland tumors: A single institution experience.

OBJECTIVE: To investigate the characteristics and treatment modalities of malignant tumors originating from the sublingual gland, as well as evaluate the therapeutic outcomes following free flap reconstruction. METHODS: A retrospective statistical analysis was conducted on the clinical data of nine patients diagnosed with malignant neoplasms tumor of the sublingual gland. RESULTS: Nine case of malignant tumors originated from the sublingual glandular tissue, encompassing eight adenoid cystic carcinoma (ACC) and a single case of bipartite differentiated carcinoma-a hybrid of epithelial-myoepithelial carcinoma and adenoid cystic carcinoma. Among the nine patients, four anterolateral thigh flaps were used (three of which were thin flaps), and five forearm flaps were also empoyed. The size of flaps varied, with the lengths ranging from 4 cm to 9 cm, and the widths ranging from 2.5 cm to 6 cm. The vessels chosen for anastomosis were the superior thyroid artery in seven cases, the facial artery in one case, and the lingual artery in one case. Among the eight patients who underwent dissection of cervical lymph nodes, metastasis were found in one case. Two patients underwent adjuvant radiotherapy. Upon postoperative follow-up, there was no recurrence in any of the nine patients . CONCLUSION: The anterolateral thigh perforator flap thinning technique can be employed for postoperative reconstruction of malignant sublingual gland tumors.

NAP1L1 regulates BIRC2 ubiquitination modification via E3 ubiquitin ligase UBR4 and hence determines hepatocellular carcinoma progression.

We have previously shown that nucleosome assembly protein 1-like 1 (NAP1L1) plays an important role in the abnormal proliferation of hepatocellular carcinoma (HCC) cells. However, the effects of NAP1L1 on the malignant behaviour of HCC cells, including cell migration, invasion and apoptosis, remain unclear. Baculoviral IAP repeat-containing 2 (BIRC2) plays a key role in initiating the abnormal proliferation, apoptotic escape and multidrug resistance of HCC cells; however, the mechanisms through which its stability is regulated in HCC remain elusive. Here, we found that knockdown of NAP1L1 inhibited the proliferation of HCC cells and activated apoptotic pathways but did not remarkably affect the migratory and invasive abilities of HCC cells. In addition, knockdown of NAP1L1 did not alter the expression of BIRC2 at the transcriptional level but substantially reduced its expression at the translational level, suggesting that NAP1L1 is involved in the post-translational modification (such as ubiquitination) of BIRC2. Furthermore, BIRC2 was highly expressed in human HCC tissues and promoted the proliferation and apoptotic escape of HCC cells. Co-immunoprecipitation (Co-IP) assay and mass spectrometry revealed that NAP1L1 and BIRC2 did not bind to each other; however, ubiquitin protein ligase E3 component n-recognin 4 (UBR4) was identified as an intermediate molecule associating NAP1L1 with BIRC2. Knockdown of NAP1L1 promoted the ubiquitin-mediated degradation of BIRC2 through the ubiquitin-protein junction of UBR4, which in turn inhibited the proliferation and apoptotic escape of HCC cells and exerted anti-tumour effects. In conclusion, this study reveals a novel mechanism through which NAP1L1 regulates the ubiquitination of BIRC2 through UBR4, thereby determining the progression of HCC. Based on this mechanism, suppression of NAP1L1 may inhibit tumour progression in patients with HCC with high protein expression of NAP1L1 or BIRC2.

Correction: MiR-4458-loaded gelatin nanospheres target COL11A1 for DDR2/SRC signaling pathway inactivation to suppress the progression of estrogen receptor-positive breast cancer.

Correction for 'MiR-4458-loaded gelatin nanospheres target COL11A1 for DDR2/SRC signaling pathway inactivation to suppress the progression of estrogen receptor-positive breast cancer' by Jie Liu et al., Biomater. Sci., 2022, 10, 4596-4611, https://doi.org/10.1039/D2BM00543C.

Algorithm for the reconstruction of the parotid region: a single institution experience.

OBJECTIVE: This study aims to discuss the characteristics and treatment methods of malignant tumors in the parotid region, as well as the therapeutic effects of immediate free flap reconstruction of soft tissue for postoperative defects. MATERIALS AND METHODS: A retrospective review was conducted on 11 cases of soft tissue flap reconstruction for postoperative defects following the resection of malignant tumors in the parotid region. Statistical analysis was performed based on clinical data. RESULTS: Among the 11 cases of malignant tumors in the parotid region, there were 2 cases of secretory carcinoma (SC) of the salivary gland, 2 cases of squamous cell carcinoma (SCC), 2 cases of carcinosarcoma, 1 case of mucoepidermoid carcinoma (MEC), 1 case of epithelial-myoepithelial carcinoma (EMC), 1 case of salivary duct carcinoma (SDC), 1 case of basal cell carcinoma (BCC), and 1 case of osteosarcoma. Among these cases, 4 were initial diagnoses and 7 were recurrent tumors. The defect repairs involved: 8 cases with anterolateral thigh free flap (ALTF), 2 cases with pectoralis major muscle flaps, and 1 case with forearm flap. The size of the flaps ranged from approximately 1 cm × 3 cm to 7 cm × 15 cm. The recipient vessels included: 4 cases with the facial artery, 4 cases with the superior thyroid artery, and 1 case with the external carotid artery. The ratio of recipient vein anastomosis was: 57% for branches of the internal jugular vein, 29% for the facial vein, and 14% for the external jugular vein. Among the 8 cases that underwent neck lymph node dissection, one case showed lymph node metastasis on pathological examination. In the initial diagnosis cases, 2 cases received postoperative radiotherapy, and 1 case received 125I seed implantation therapeutic treatment after experiencing two recurrences. Postoperative follow-up revealed that 2 cases underwent reoperation due to local tumor recurrence, and there were 2 cases lost to follow-up. The survival outcomes after treatment included: one case of distant metastasis and one case of death from non-cancerous diseases. CONCLUSION: Immediate soft tissue flap reconstruction is an important and valuable option to address postoperative defects in patients afflicted with malignant tumors in the parotid region.

One case of sublingual gland mucosa-associated lymphoid tissue lymphoma.

Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of marginal zone B-cell lymphoma that occurs outside the lymph nodes in mucosal tissue. It accounts for 6-8 % of non-Hodgkin's lymphomas. MALT lymphoma of the salivary gland is a rare disease, with primary tumors in the salivary gland accounting for 2-5 % of salivary gland tumors. The most common site is the parotid gland (80 %), followed by the submandibular gland (14 %), minor salivary glands, and sublingual gland (5 %). Patients with salivary gland MALT lymphoma often have autoimmune diseases such as Sjogren's syndrome and rheumatoid arthritis. Primary malignant tumors of the sublingual gland account for less than 1 % of cases, and preoperative diagnosis is difficult, often requiring biopsy for confirmation. To our knowledge, there are no reports of MALT lymphoma arising from the sublingual gland. We report a case of MALT lymphoma originating from the sublingual gland in a patient with a history of hypertension, diabetes, cerebral infarction, and non-traumatic numbness of the right lower limb.

Identification of SEC61G as a Diagnostic and Prognostic Biomarker in Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) is a heterogeneous malignancy originating from the oral mucosal epithelium. Detecting novel biomarkers can offer crucial information on disease aggressiveness and expected clinical outcomes for individual patients. SEC61G, an aberrantly expressed gene in various cancers, has been associated with negative clinical outcomes. However, its expression and clinical significance in OSCC is still unclear. In the present study, we investigated the SEC61G expression level in OSCC using bioinformatic and immunohistochemical analyses. Additionally, our findings revealed a significant correlation between SEC61G expression and clinicopathological characteristics, as well as a worse prognosis in OSCC patients. Notably, flow cytometry analysis on patient samples revealed that SEC61G expression was also linked to decreased immune infiltration in OSCC patients. In conclusion, our study provides evidence supporting SEC61G's role as a potential diagnostic, prognostic, and therapeutic marker in OSCC.

Host ALDH2 deficiency aggravates nonalcoholic steatohepatitis through gut-liver axis.

Nonalcoholic steatohepatitis (NASH) is the major cause of liver dysfunction. Animal and population studies have shown that mitochondrial aldehyde dehydrogenase (ALDH2) is implicated in fatty liver disease. However, the role of ALDH2 in NASH and the underlying mechanisms remains unclear. To address this issue, ALDH2 knockout (ALDH2-/-) mice and wild-type littermate mice were fed a methionine-and choline-deficient (MCD) diet to induce a NASH model. Fecal, serum, and liver samples were collected and analyzed to investigate the impact of the gut microbiota and bile acids on this process. We found that MCD-fed ALDH2-/- mice exhibited increased serum pro-inflammation cytokines, hepatic inflammation and fat accumulation than their wild-type littermates. MCD-fed ALDH2-/- mice exhibited worsened MCD-induced intestinal inflammation and barrier damage, and gut microbiota disorder. Furthermore, mice receiving microbiota from MCD-fed ALDH2-/- mice had increased severity of NASH compared to those receiving microbiota from MCD-fed wild-type mice. Notably, the intestinal Lactobacillus was significantly reduced in MCD-fed ALDH2-/- mice, and gavage with Lactobacillus cocktail significantly improved MCD-induced NASH. Finally, we found that ALDH2-/- mice had reduced levels of bile salt hydrolase and specific bile acids, especially lithocholic acid (LCA), accompanied by downregulated expression of the intestinal FXR-FGF15 pathway. Supplementation of LCA in ALDH2-/- mice upregulated intestinal FXR-FGF15 pathway and alleviated NASH. In summary, ALDH2 plays a critical role in the development of NASH through modulation of gut microbiota and bile acid. The findings suggest that supplementing with Lactobacillus or LCA could be a promising therapeutic approach for treating NASH exacerbated by ALDH2 deficiency.

Microtiter plate-based chemistry and in situ screening: SuFEx-enabled lead discovery of selective AChE inhibitors.

Sulphur fluoride exchange (SuFEx) is a category of click chemistry that enables covalent linking of modular units through sulphur connective hubs. Here, we reported an efficient synthesis and in situ screening method for building a library of sulphonamides on the picomolar scale by SuFEx reaction between a sulphonyl fluoride (RSO2F) core and primary or secondary amines. This biocompatible SuFEx reaction would allow us to rapidly synthesise sulphonamide molecules, and evaluate their ChE inhibitory activity. Compound T14-A24 was identified as a reversible, competitive, and selective AChE inhibitor (Ki = 22 nM). The drug-like evaluation showed that T14-A24 had benign BBB penetration, remarkable neuroprotective effect, and safe toxicological profile. In vivo behavioural study showed that T14-A24 treatment improved the Aß1 - 42-induced cognitive impairment, significantly prevented the effects of Aß1 - 42 toxicity. Therefore, this SuFEx click reaction can accelerate the discovery of lead compounds.

Sulfur-fluoride exchange (SuFEx)-enabled lead discovery of AChE inhibitors by fragment linking strategies.

SuFEx click chemistry has been a method for the rapid synthesis of functional molecules with desirable properties. Here, we demonstrated a workflow that allows for in situ synthesis of sulfonamide inhibitors based on SuFEx reaction for high-throughput testing of their cholinesterase activity. According to fragment-based drug discovery (FBDD), sulfonyl fluorides [R-SO2F] with moderate activity were identified as fragment hits, rapidly diversified into 102 analogs in SuFEx reactions, and the sulfonamides were directly screened to yield drug-like inhibitors with 70-fold higher potency (IC50 = 94 nM). Moreover, the improved molecule J8-A34 can ameliorate cognitive function in Aß1-42-induced mouse model. Since this SuFEx linkage reaction succeeds on picomole scale for direct screening, this methodology can accelerate the development of robust biological probes and drug candidates.

The antitumour effects of caloric restriction are mediated by the gut microbiome.

Calorie restriction (CR) and intermittent fasting (IF) without malnutrition reduce the risk of cancer development. Separately, CR and IF can also lead to gut microbiota remodelling. However, whether the gut microbiota has a role in the antitumour effect related to CR or IF is still unknown. Here we show that CR, but not IF, protects against subcutaneous MC38 tumour formation through a mechanism that is dependent on the gut microbiota in female mice. After CR, we identify enrichment of Bifidobacterium through 16S rRNA sequencing of the gut microbiome. Moreover, Bifidobacterium bifidum administration is sufficient to rescue the antitumour effect of CR in microbiota-depleted mice. Mechanistically, B. bifidum mediates the CR-induced antitumour effect through acetate production and this effect is also dependent on the accumulation of interferon-γ+CD8+ T cells in the tumour microenvironment. Our results demonstrate that CR can modulate the gut taxonomic composition, which should be of oncological significance in tumour growth kinetics and cancer immunosurveillance.

Untangling determinants of gut microbiota and tumor immunologic status through a multi-omics approach in colorectal cancer.

The changes in gut microbiota have been implicated in colorectal cancer (CRC). The interplays between the host and gut microbiota remain largely unclear, and few studies have investigated these interplays using integrative multi-omics data. In this study, large-scale multi-comic datasets, including microbiome, metabolome, bulk transcriptomics and single cell RNA sequencing of CRC patients, were analyzed individually and integrated through advanced bioinformatics methods. We further examined the clinical relevance of these findings in the mice recolonized with microbiota from human. We found that CRC patients had distinct microbiota compositions compared to healthy controls. A machine-learning model was developed with 28 biomarkers for detection of CRC, which had high accuracy and clinical applicability. We identified multiple significant correlations between genera and well-characterized genes, suggesting the potential role of gut microbiota in tumor immunity. Further analysis showed that specific metabolites worked as profound communicators between these genera and tumor immunity. Integrating microbiota and metabolome perspectives, we cataloged gut taxonomic and metabolomic features that represented the key multi-omics signature of CRC. Furthermore, gut microbiota transplanted from CRC patients compromised the response of CRC to immunotherapy. These phenotypes were strongly associated with the alterations in gut microbiota, immune cell infiltration as well as multiple metabolic pathways. The comprehensive interplays across multi-comic data of CRC might explain how gut microbiota influenced tumor immunity. Hence, we proposed that modifying the CRC microbiota using healthy donors might serve as a promising strategy to improve response to immunotherapy.

Fluorosulfate-containing pyrazole heterocycles as selective BuChE inhibitors: structure-activity relationship and biological evaluation for the treatment of Alzheimer's disease.

Novel scaffolds are expected to treat Alzheimer's disease, pyrazole-5-fluorosulfates were found as selective BuChE inhibitors. Compounds K1-K26 were assayed for ChE inhibitory activity, amongst them, compound K3 showed potent BuChE and hBuChE inhibition (IC50 = 0.79 µM and 6.59 µM). SAR analysis showed that 1-, 3-, 4-subtituent and 5-fluorosulfate of pyrazole ring affected BuChE inhibitory activity. Molecular docking showed that the fluorosulfate increased the binding affinity of hBuChE through π-sulphur interaction. Compound K3 was a reversible, mixed and non-competitive BuChE inhibitor (Ki = 0.77 µM) and showed remarkable neuroprotection, safe toxicological profile and BBB penetration. In vivo behavioural study showed that K3 treatment improved the Aß1 - 42-induced cognitive impairment, and significantly prevented the effects of Aß1 - 42 toxicity. Therefore, selective BuChE inhibitor K3 has potential to be further developed as AD therapeutics.

MiR-4458-loaded gelatin nanospheres target COL11A1 for DDR2/SRC signaling pathway inactivation to suppress the progression of estrogen receptor-positive breast cancer.

RNA interference is a promising way to treat cancer and the construction of a stable drug delivery system is critically important for its application. Gelatin nanospheres (GNs) comprise a biodegradable drug vehicle with excellent biocompatibility, but there are limited studies on its delivery and role in the stabilization of miRNA and siRNA. Breast cancer is the most diagnosed type of female cancer worldwide. Abnormal miRNA expression is closely related to the occurrence and progression of estrogen receptor-positive (ER+) breast cancer. In this study, miR-4458 was upregulated in ER+ breast cancer and could inhibit MCF-7 cell viability, colony formation, migration, and invasion. Collagen type XI alpha 1 (COL11A1) was identified as a directly interacting protein of miR-4458 and an important component of the extracellular matrix. High COL11A1 expression was positively correlated with poor prognosis, lower overall survival, disease-free survival, and a late tumor-node-metastasis stage. COL11A1 knockdown could inhibit MCF-7 cell migration and invasion. GNs were used to load a miR-4458 mimic or COL11A1 siRNA (si-COL11A1) to achieve sustained and controlled release in xenograft nude mice. Their tumor volume was decreased, tumor cell apoptosis was promoted, and hepatic metastasis was significantly inhibited. Moreover, the DDR2/SRC signaling pathway was inactivated after transfection with the miR-4458 mimic and si-COL11A1. In conclusion, GNs can be potentially used to deliver siRNA or miRNA, and miR-4458 and COL11A1 can be possible targets for ER+ breast cancer treatment.

Lacticaseibacillus paracasei sh2020 induced antitumor immunity and synergized with anti-programmed cell death 1 to reduce tumor burden in mice.

The gut microbiota was emerging as critical regulatory elements in shaping the outcome of cancer immunotherapy. However, the underlying mechanisms by which the gut commensal species enhance antitumor immunity remain largely unexplored. Here, we show that the gut microbiota from healthy individuals conferred considerable sensitivity to anti-PD-1 in the colorectal cancer (CRC) tumor-bearing mice, whereas gut microbiota from CRC patients failed to do so. By 16S rRNA gene sequencing, we identified Lactobacillus that was significantly increased in the mice with good response to anti-PD-1, and significantly correlated with anti-tumor immunity. After a series of screening, we isolated a novel Lacticaseibacillus strain, named L. paracasei sh2020. L. paracasei sh2020 showed the most notable anti-tumor immunity in the mice with gut dysbiosis. Mechanistically, the antitumor immune response elicited by L. paracasei sh2020 was dependent on CD8+ T cell. In vitro and in vivo studies revealed that L. paracasei sh2020 stimulation triggered the upregulated expression of CXCL10 in the tumors and subsequently enhanced CD8+ T cell recruitment. Meanwhile, the modulation of gut microbiota caused by L. paracasei sh2020 enhanced its antitumor effect and gut barrier function. Overall, our study offered novel insights into the mechanism by which gut microbiota shaped the outcome of cancer immunotherapy and, more importantly, the novel strain L. paracasei sh2020 might serve as an easy and effective way to promote anti-PD-1 effect in clinical practice.

Gut and Cutaneous Microbiome Featuring Abundance of Lactobacillus reuteri Protected Against Psoriasis-Like Inflammation in Mice.

BACKGROUND: Psoriasis is a chronic autoinflammatory skin disease, and its aetiology remains incompletely understood. Recently, gut microbial dysbiosis is found to be tightly associated with psoriasis. OBJECTIVE: We sought to reveal the causal role of gut microbiota dysbiosis in psoriasis pathogenesis and investigate the protective effect of healthy commensal bacteria against imiquimod -induced psoriasis-like skin response. METHODS: By using fecal microbial transplantation (FMT), 16S rRNA gene-based taxonomic profiling and Lactobacillus supplement, we have assessed the effect of FMT from healthy individuals on psoriasis-like skin inflammation and associated immune disorders in imiquimod-induced psoriasis mice. RESULTS: Here, by using psoriasis mice humanized with the stools from healthy donors and psoriasis patients, the imiquimod-induced psoriasis in mice with psoriasis patient stool was found to be significantly aggravated as compared to the mice with healthy donor stools. Further analysis showed fecal microbiota of healthy individuals protected against Treg/Th17 imbalance in psoriasis. Moreover, we found the gut and skin microbiome in mice receipted with gut microbiota of healthy individuals (HD) differed from those of mice receipted with gut microbiota of psoriasis patients (PSD). 16S rRNA sequencing revealed that Lactobacillus reuteri was greatly enriched in fecal and cutaneous microbiome of HD mice as compared to PSD mice. Intriguingly, supplement with Lactobacillus reuteri was sufficient to increase the expression of anti-inflammatory gene IL-10, reduce Th17 cells counts and confer resistance to imiquimod-induced inflammation on the mice with gut microbiota dysbiosis. CONCLUSION: Our results suggested that the gut microbiota dysbiosis is the potential causal factor for psoriasis and the gut microbiota may serve as promising therapy target for psoriasis patients.

Low EGR1 expression predicts poor prognosis in clear cell renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is resistant to conventional therapy due to the deletion of the von Hippel-Lindau (VHL) gene, and novel treatment options are urgently needed. Here, using tissue microarray analysis of 445 cancer tissues and 326 adjacent normal renal tissues obtained from patients with ccRCC, we present the early growth response-1 (EGR1) protein levels are significantly decreased in ccRCC cancer tissues. Consistently, the EGR1 mRNA expression also decreased in cancer tissues based on the transcriptomic data for 599 tumor and normal samples from The Cancer Genome Atlas. Moreover, Patients with ccRCC presenting low EGR1 expression are more prone to exhibit metastasis and a poor prognosis than those with high EGR1 expression. By multivariate Cox regression analysis, EGR1 is determined to serve as an independent prognostic factor for patients with ccRCC. Further cellular biochemical function analyses show that EGR1 may inhibit proliferation, invasion and metastasis of ccRCC. These findings will deepen our understanding of EGR1 function and shed light on precise treatment for ccRCC patients.

miR-506-loaded gelatin nanospheres target PENK and inactivate the ERK/Fos signaling pathway to suppress triple-negative breast cancer aggressiveness.

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. Some microRNAs (miRNAs) were abnormally expressed in TNBC, and they are closely related to the occurrence and progression of TNBC. Here, we found that miR-506 was significantly downregulated in TNBC and relatively lower miR-506 expression predicted a poorer prognosis. Moreover, we found that miR-506 could inhibit MDA-MB-231 cell viability, colony formation, migration, and invasion, and suppress the ERK/Fos oncogenic signaling pathway through upregulating its direct target protein proenkephalin (PENK). Therefore, miR-506 was proposed as a nucleic acid drug for TNBC therapy. However, miRNA is unstable in vivo, which limiting its application as a therapeutic drug via conventional oral or injected therapies. Here, a gelatin nanosphere (GN) delivery system was applied for the first time to load exogenous miRNA. Exogenous miR-506 mimic was loaded on GNs and injected into the in situ TNBC animal model, and the miR-506 could achieve sustained and controlled release. The results confirmed that overexpression of miR-506 and PENK in vivo through loading on GNs inhibited in situ triple-negative breast tumor growth and metastasis significantly in the xenograft model. Moreover, we indicated that the ERK/Fos signaling pathway was intensively inactivated after overexpression of miR-506 and PENK both in vitro and in vivo, which was further validated by the ERK1/2-specific inhibitor SCH772984. In conclusion, this study demonstrates that miR-506-loaded GNs have great potential in anti-TNBC aggressiveness therapy.

Database Study on the Expression and Purification of Membrane Proteins.

Membrane proteins are crucial for biological processes, and many of them are important to drug targets. Understanding the three-dimensional structures of membrane proteins are essential to evaluate their bio-function and drug design. High-purity membrane proteins are important for structural determination. Membrane proteins have low yields and are difficult to purify because they tend to aggregate. We summarized membrane protein expression systems, vectors, tags, and detergents, which have deposited in the Protein Data Bank (PDB) in recent four-and-a-half years. Escherichia coli is the most expression system for membrane proteins, and HEK293 cells are the most commonly cell lines for human membrane protein expression. The most frequently vectors are pFastBac1 for alpha-helical membrane proteins, pET28a for beta-barrel membrane proteins, and pTRC99a for monotopic membrane proteins. The most used tag for membrane proteins is the 6×His-tag. FLAG commonly used for alpha-helical membrane proteins, Strep and GST for beta- barrel and monotopic membrane proteins, respectively. The detergents and their concentrations used for alpha-helical, beta-barrel, and monotopic membrane proteins are different, and DDM is commonly used for membrane protein purification. It can guide the expression and purification of membrane proteins, thus contributing to their structure and bio function studying.

Pectin supplement significantly enhanced the anti-PD-1 efficacy in tumor-bearing mice humanized with gut microbiota from patients with colorectal cancer.

Background: Anti-PD-1-based immunotherapy has emerged as a promising therapy for several cancers. However, it only benefits a small subset of colorectal cancer (CRC) patients. Mounting data supports the pivotal role of gut microbiota in shaping immune system. Pectin, a widely consumed soluble fiber, has been reported to ameliorate the imbalance of gut microbiota. Therefore, we aimed to explore the effect and the underlying mechanisms of pectin in improving anti-PD-1 mAb efficacy. Methods: The C57BL/6 mice were treated with a broad-spectrum antibiotic (ATB) cocktail to depleted endogenous gut microbiota and subsequently humanized with feces from healthy controls or newly diagnosed CRC patients. The antitumor efficacies of anti-PD-1 mAb combined with or without pectin were assessed using these mice. Flow cytometry and immunohistochemistry (IHC) were conducted to investigate the tumor immune microenvironment after treatment. The gut microbiota profiles and short-chain fatty acids (SCFAs) levels were determined by 16S ribosomal RNA (16S rRNA) gene sequencing and gas chromatography-mass spectrometry (GC-MS), respectively. The effect of gut microbiota on anti-PD-1 mAb efficacy after pectin supplement was further tested by fecal microbiota transplantation (FMT). Results: The anti-PD-1 mAb efficacy was largely impaired in the mice humanized with feces from newly diagnosed CRC patients compared to those from healthy controls. However, pectin significantly enhanced the anti-PD-1 mAb efficacy in the tumor-bearing mice humanized with CRC patient gut microbiota. Flow cytometry and IHC analysis revealed increased T cell infiltration and activation in the tumor microenvironment of mice treated with anti-PD-1 mAb plus pectin. In vivo depletion of CD8+ T cells diminished the anti-tumor effect of anti-PD-1 mAb combined with pectin. 16S rRNA gene sequencing showed that pectin significantly increased gut microbial diversity and beneficially regulated microbial composition. In addition, we identified unique bacterial modules that were significantly enriched in the anti-PD-1 mAb + pectin group, which composed of butyrate-producing bacteria indicative of good response to immunotherapy. Meanwhile, GC-MS showed that pectin altered the level of SCFA butyrate. Furthermore, butyrate, a main product of dietary fiber in gut microbial fermentation, was found to be sufficient to promote T cells infiltration and thus enhance the efficacy of anti-PD-1 mAb. In addition, FMT demonstrated the effects of pectin were dependent on gut microbiota. Importantly, the beneficial effects of pectin were confirmed in the mice humanized with gut microbiota from patient with resistance to anti-PD-1 mAb. Conclusion: Pectin facilitated the anti-PD-1 mAb efficacy in CRC via regulating the T cell infiltration in the tumor microenvironment, which was potentially mediated by the metabolite butyrate.