Computational fluid dynamics simulation of a novel bioreactor forsophorolipid production

This paper describes three-dimensional computational fluid dynamics(CFD) simulations of gas–liquid flow in a novel laboratory-scale bioreactor contained dual ventilation-pipe and double sieve-plate bioreactor(DVDSB)used for sophorolipid(SL) production. To evaluate the role of hydrodynamics in reactor design, the comparisons between conventional fed-batch fermenter and DVDSB on the hydrodynamic behavior are predicted by the CFD methods. Important hydrodynamic parameters of the gas–liquid two-phase system such as the liquid phase velocity field, turbulent kinetic energy and volume-averaged overall and time-averaged local gas holdups were simulated and analyzed in detail. The numerical results were also validated by experimental measurements of overall gas holdups. The yield of sophorolipids was significantly improved to 484 g·L^(-1)with a 320 h fermentation period in the new reactor.

Community Structure of Endophytic Fungi in Ginseng and Its Correlation Analysis with Active Components

[Objectives]The paper was to explore the correlation between active components of ginseng and community structure of endophytic fungi in ginseng under different cultivation methods.[Methods]Using ginsengs under two main planting patterns in Huanren County,Liaoning Province as the samples,the community structure of endophytic fungi was studied by molecular means,and the chemical components were identified and the content of chemical markers was measured via LC-MS.Moreover,the correlation between medicinal components of ginseng and diversity of endophytic fungal flora was analyzed.[Results]The diversity and active components of endophytic fungi of ginseng were different.The diversity analysis showed that the medicinal components of ginseng were positively correlated with some fungal groups in ginseng.[Conclusions]Artificial intervention in the planting process would affect the endophytic fungi in medicinal materials,and further affect the chemical components of ginseng medicinal materials.

HTR2A agonists play a therapeutic role by restricting ILC2 activation in papain-induced lung inflammation

Group 2 innate lymphoid cells(ILC2s)are a category of heterogeneous cells that produce the cytokines IL-5 and IL-13,which mediate the type 2 immune response.However,specific drug targets on lung ILC2s have rarely been reported.Previous studies have shown that type 2 cytokines,such as IL-5 and IL-13,are related to depression.Here,we demonstrated the negative correlation between the depression-associated monoamine neurotransmitter serotonin and secretion of the cytokines IL-5 and IL-13 by ILC2s in individuals with depression.Interestingly,serotonin ameliorates papain-induced lung inflammation by suppressing ILC2 activation.Our data showed that the serotonin receptor HTR2A was highly expressed on ILC2s from mouse lungs and human PBMCs.Furthermore,an HTR2A selective agonist(DOI)impaired ILC2 activation and alleviated the type 2 immune response in vivo and in vitro.Mice with ILC2-specific depletion of HTR2A(Il5^(cre/+)·Htr2a^(flox/flox)mice)abolished the DOI-mediated inhibition of ILC2s in a papain-induced mouse model of inflammation.In conclusion,serotonin and DOI could restrict the type 2 lung immune response,indicating a potential treatment strategy for type 2 lung inflammation by targeting HTR2A on ST2+ILC2s.

Vitamin B6 regulates IL-33 homeostasis to alleviate type 2 inflammation

Interleukin-33(IL-33)is a crucial nuclear cytokine that induces the type 2 immune response and maintains immune homeostasis.The fine-tuned regulation of IL-33 in tissue cells is critical to control of the type 2 immune response in airway inflammation,but the mechanism is still unclear.Here,we found that healthy individuals had higher phosphate-pyridoxal(PLP,an active form of vitamin B6)concentrations in the serum than asthma patients.Lower serum PLP concentrations in asthma patients were strongly associated with worse lung function and inflammation.In a mouse model of lung inflammation,we revealed that PLP alleviated the type 2 immune response and that this inhibitory effect relied on the activity of IL-33.A mechanistic study showed that in vivo,pyridoxal(PL)needed to be converted into PLP,which inhibited the type 2 response by regulating IL-33 stability.In mice heterozygous for pyridoxal kinase(PDXK),the conversion of PL to PLP was limited,and IL-33 levels were increased in the lungs,aggravating type 2 inflammation.Furthermore,we found that the mouse double minute 2 homolog(MDM2)protein,an E3 ubiquitin-protein ligase,could ubiquitinate the N-terminus of IL-33 and sustain IL-33 stability in epithelial cells.PLP reduced MDM2-mediated IL-33 polyubiquitination and decreased the level of IL-33 through the proteasome pathway.In addition,inhalation of PLP alleviated asthma-related effects in mouse models.In summary,our data indicate that vitamin B6 regulates MDM2-mediated IL-33 stability to constrain the type 2 response,which might help develop a potential preventive and therapeutic agent for allergy-related diseases.

A human antibody potently neutralizes RSV by targeting the conserved hydrophobic region of prefusion F

Respiratory syncytial virus(RSV) continues to pose serious threats to pediatric populations due to the lack of a vaccine and effective antiviral drugs. RSV fusion(F) glycoprotein mediates viral-host membrane fusion and is a key target for neutralizing antibodies. We generated 23 full-human monoclonal antibodies(hm Abs) against prefusion F protein(pre-F) from a healthy adult with natural RSV infection by single B cell cloning technique. A highly potent RSV-neutralizing hm Ab, named as 25-20, is selected, which targets a new site Φ-specific epitope. Site-directed mutagenesis and structural modelling analysis demonstrated that 25-20 mainly targets a highly conserved hydrophobic region located at the a4 helix and a1 helix of pre-F, indicating a site of vulnerability for drug and vaccine design. It is worth noting that 25-20 uses an unreported inferred germline(i GL) that binds very poorly to pre-F, thus high levels of somatic mutations are needed to gain high binding affinity with pre-F. Our observation helps to understand the evolution of RSV antibody during natural infection. Furthermore, by in silico prediction and experimental verification, we optimized 25-20 with KD values as low as picomolar range. Therefore, the optimized 25-20 represents an excellent candidate for passive protection against RSV infection.

Trim28 citrullination maintains mouse embryonic stem cell pluripotency via regulating Nanog and Klf4 transcription

Protein citrullination,including histone H1 and H3 citrullination,is important for transcriptional regulation,DNA damage response,and pluripotency of embryonic stem cells(ESCs).Tripartite motif containing 28(Trim28),an embryonic development regulator involved in ESC self-renewal,has recently been identified as a novel substrate for citrullination by Padi4.However,the physiological functions of Trim28 citrullination and its role in regulating the chromatin structure and gene transcription of ESCs remain unknown.In this paper,we show that Trim28 is specifically citrullinated in mouse ESCs(m ESCs),and that the loss of Trim28 citrullination induces loss of pluripotency.Mechanistically,Trim28 citrullination enhances the interaction of Trim28with Smarcad1 and prevents chromatin condensation.Additionally,Trim28 citrullination regulates m ESC pluripotency by promoting transcription of Nanog and Klf4 which it does by increasing the enrichment of H3K27ac and H3K4me3 and decreasing the enrichment of H3K9me3 in the transcriptional regulatory region.Thus,our findings suggest that Trim28citrullination is the key for the epigenetic activation of pluripotency genes and pluripotency maintenance of ESCs.Together,these results uncover a role Trim28 citrullination plays in pluripotency regulation and provide novel insight into how citrullination of proteins other than histones regulates chromatin compaction.

Assembly of JAZ–JAZ and JAZ–NINJA complexes in jasmonate signaling

Jasmonates(JAs)are plant hormones with crucial roles in development and stress resilience.They activate MYC transcription factors by mediating the proteolysis of MYC inhibitors called JAZ proteins.In the absence of JA,JAZ proteins bind and inhibit MYC through the assembly of MYC–JAZ–Novel Interactor of JAZ(NINJA)–TPL repressor complexes.However,JAZ and NINJA are predicted to be largely intrinsically unstructured,which has precluded their experimental structure determination.Through a combination of biochemical,mutational,and biophysical analyses and AlphaFold-derived ColabFold modeling,we characterized JAZ–JAZ and JAZ–NINJA interactions and generated models with detailed,high-confidence domain interfaces.We demonstrate that JAZ,NINJA,and MYC interface domains are dynamic in isolation and become stabilized in a stepwise order upon complex assembly.By contrast,most JAZ and NINJA regions outside of the interfaces remain highly dynamic and cannot be modeled in a single conformation.Our data indicate that the small JAZ Zinc finger expressed in Inflorescence Meristem(ZIM)motif mediates JAZ–JAZ and JAZ–NINJA interactions through separate surfaces,and our data further suggest that NINJA modulates JAZ dimerization.This study advances our understanding of JA signaling by providing insights into the dynamics,interactions,and structure of the JAZ–NINJA core of the JA repressor complex.

Colorectal cancer-derived extracellular vesicles induce liver premetastatic immunosuppressive niche formation to promote tumor early liver metastasis

Dear Editor,To date,the effect of colorectal cancer(CRC)-derived extracellular vesicles(EVs)on liver pre-metastatic niche(PMN)remain incompletely understood.1 To investigate the role of CRC-derived EVs in the remodeling of the liver PMN,we isolated EVs from CT26 cell culture supernatant.The characteristics of EVs(the morphology,size,and markers)were identified by transmission electron microscopy(TEM),Nanoparticle Tracking Analysis(NTA),and western blotting(Supplementary Fig.S1a–e).Then,BALB/c mice with an intact liver immune status were pretreated with CRCderived EVs and phosphate-buffered saline(PBS)for one month,and a liver metastasis model was established via spleen injection of tumor cells to determine whether EVs influence liver metastasis(Fig.1a).Two hours after the operation,in vivo imaging indicated that the animal model was successfully established,and the tumor fluorescence intensity in the liver was consistent between the two groups(Supplementary Fig.S2a,b).Amazingly,the liver tumor fluorescence intensity in the EVs group was significantly stronger than that in the PBS group after 24 h(Fig.1b;Supplementary Fig.S2c,d).The number of liver tumor nodules in the EVs group was also significantly higher than that in the PBS group on day 4(Fig.1c;Supplementary Fig.S2e,f).

Targeting CRL4 suppresses chemoresistant ovarian cancer growth by inducing mitophagy

Chemoresistance has long been the bottleneck of ovarian cancer(OC)prognosis.It has been shown that mitochondria play a crucial role in cell response to chemotherapy and that dysregulated mitochondrial dynamics is intricately linked with diseases like OC,but the underlying mechanisms remain equivocal.Here,we demonstrate a new mechanism where CRL4^(CUL4A/DDB1)manipulates OC cell chemoresistance by regulating mitochondrial dynamics and mitophagy.CRL4^(CUL4A/DDB1)depletion enhanced mitochondrial fission by upregulating AMPKα^(Thr172)and MFF^(Ser172/Ser146)phosphorylation,which in turn recruited DRP1 to mitochondria.CRL4^(CUL4A/DDB1)loss stimulated mitophagy through the Parkin-PINK1 pathway to degrade the dysfunctional and fragmented mitochondria.Importantly,CRL4^(CUL4A/DDB1)loss inhibited OC cell proliferation,whereas inhibiting autophagy partially reversed this disruption.Our findings provide novel insight into the multifaceted function of the CRL4 E3 ubiquitin ligase complex in regulating mitochondrial fission,mitophagy,and OC chemoresistance.Disruption of CRL4^(CUL4A/DDB1)and mitophagy may be a promising therapeutic strategy to overcome chemoresistance in OC.

Key residues of the receptor binding motif in the spike protein of SARS-CoV-2 that interact with ACE2 and neutralizing antibodies

Coronavirus disease 2019(COVID-19),caused by the novel human coronavirus SARS-CoV-2,is currently a major threat to public health worldwide.The viral spike protein binds the host receptor angiotensin-converting enzyme 2(ACE2)via the receptor-binding domain(RBD),and thus is believed to be a major target to block viral entry.Both SARS-CoV-2 and SARS-CoV share this mechanism.Here we functionally analyzed the key amino acid residues located within receptor binding motif of RBD that may interact with human ACE2 and available neutralizing antibodies.The in vivo experiments showed that immunization with either the SARS-CoV RBD or SARS-CoV-2 RBD was able to induce strong clade-specific neutralizing antibodies in mice;however,the cross-neutralizing activity was much weaker,indicating that there are distinct antigenic features in the RBDs of the two viruses.This finding was confirmed with the available neutralizing monoclonal antibodies against SARS-CoV or SARS-CoV-2.It is worth noting that a newly developed SARS-CoV-2 human antibody,HA001,was able to neutralize SARS-CoV-2,but failed to recognize SARS-CoV.Moreover,the potential epitope residues of HA001 were identified as A475 and F486 in the SARS-CoV-2 RBD,representing new binding sites for neutralizing antibodies.Overall,our study has revealed the presence of different key epitopes between SARS-CoV and SARSCoV-2,which indicates the necessity to develop new prophylactic vaccine and antibody drugs for specific control of the COVID-19 pandemic although the available agents obtained from the SARS-CoV study are unneglectable.

The function and potential drug targets of tumour-associated Tregs for cancer immunotherapy

Regulatory T cells(Tregs) play an important role in maintaining self-tolerance and immune homeostasis, but they also play a negative role in evoking effective antitumour immune responses. There is ample evidence indicating that the depletion of Tregs or the inhibition of Treg function will enhance antitumour effects. However, it is unclear which surface molecules of Tregs are suitable targets for tumour immunotherapy with minimal toxic side effects, which is a central theme in the field of Treg-targeted immunotherapy. In this review, we focus on the regulatory mechanisms of Tregs, including intrinsic and extrinsic factors within the tumour microenvironment, and we address potential drug targets on Tregs for immunotherapy.

Cancer metabolism and tumor microenvironment:fostering each other?

The changes associated with malignancy are not only in cancer cells but also in environment in which cancer cells live.Metabolic reprogramming supports tumor cells’high demand of biogenesis for their rapid proliferation,and helps tumor cells to survive under certain genetic or environmental stresses.Emerging evidence suggests that metabolic alteration is ultimately and tightly associated with genetic changes,in particular the dysregulation of key oncogenic and tumor suppressive signaling pathways.Cancer cells activate HIF signaling even in the presence of oxygen and in the absence of growth factor stimulation.This cancer metabolic phenotype,described firstly by German physiologist Otto Warburg,ensures enhanced glycolytic metabolism for the biosynthesis of macromolecules.The conception of metabolite signaling,i.e.,metabolites are regulators of cell signaling,provides novel insights into how reactive oxygen species(ROS)and other metabolites deregulation may regulate redox homeostasis,epigenetics,and proliferation of cancer cells.Moreover,the unveiling of noncanonical functions of metabolic enzymes,such as the moonlighting functions of phosphoglycerate kinase 1(PGK1),reassures the importance of metabolism in cancer development.The metabolic,microRNAs,and ncRNAs alterations in cancer cells can be sorted and delivered either to intercellular matrix or to cancer adjacent cells to shape cancer microenvironment via media such as exosome.Among them,cancer microenvironmental cells are immune cells which exert profound effects on cancer cells.Understanding of all these processes is a prerequisite for the development of a more effective strategy to contain cancers.

Lactate anions participate in T cell cytokine production and function

After antigen stimulation, T cells preferentially increase aerobic glycolysis to meet the bioenergetic and biosynthetic demands of T cell activation, proliferation, and effector functions. Lactate, a by-product of glycolysis, has been reported to function as an important energy source and signaling molecule. Here, we found that lactate anions are involved in cytokine production in Tcells after TCR activation. During ex vivo T cell activation, the addition of excess sodium lactate(Na L) increased the production of cytokines(such as IFNγ/IL-2/TNFα) more than the addition of sodium chloride(NaCl). This enhanced cytokine production was dependent on TCR/CD3 activation but not CD28 activation. In vivo, Na L treatment inhibited tumour growth in subcutaneously transplanted tumour models in a T cell-dependent manner, which was consistent with increased T cell cytokine production in the Na L treatment group compared to the Na Cl treatment group. Furthermore, a mechanistic experiment showed that this enhanced cytokine production was regulated by GAPDH-mediated post-transcriptional regulation. Taken together, our findings indicate a new regulatory mechanism involved in glycolysis that promotes T cell function.

Protective humoral immunity in SARS-CoV-2 infected pediatric patients

After the rapid spread of SARS-CoV-2 in Wuhan,China,at the beginning of 2020,about 1.5 million confirmed cases and over 80,000 deaths have been reported around 200 countries and territories all over the world and the number continues to increase.However,we still have limited knowledge of this new coronavirus,especially the interaction between SARS-CoV-2 and our immune system.

TRIM34 attenuates colon inflammation and tumorigenesis by sustaining barrier integrity

Loss of the colonic inner mucus layer leads to spontaneously severe colitis and colorectal cancer.However,key host factors that may control the generation of the inner mucus layer are rarely reported.Here,we identify a novel function of TRIM34 in goblet cells(GCs)in controlling inner mucus layer generation.Upon DSS treatment,TRIM34 deficiency led to a reduction in Muc2 secretion by GCs and subsequent defects in the inner mucus layer.This outcome rendered TRIM34-deficient mice more susceptible to DSS-induced colitis and colitis-associated colorectal cancer.Mechanistic experiments demonstrated that TRIM34 controlled TLR signaling-induced Nox/Duox-dependent ROS synthesis,thereby promoting the compound exocytosis of Muc2 by colonic GCs that were exposed to bacterial TLR ligands.Clinical analysis revealed that TRIM34 levels in patient samples were correlated with the outcome of ulcerative colitis(UC)and the prognosis of rectal adenocarcinoma.This study indicates that TRIM34 expression in GCs plays an essential role in generating the inner mucus layer and preventing excessive colon inflammation and tumorigenesis.

Development Trajectories in the Biotechnology Industry:China versus Leading Countries

The present paper examines China＇s biotechnology industry from a global perspective and explores how its development trajectory differs from that of countries that are leaders in biotechnology. We draw on diverse data to demonstrate the unique development trajectory of the industry in China. China has benefited through targeted spin-offs of R＆D-oriented foreign direct investment from developed countries driven by the effects of globalization, government-encouraged collaboration between the domestic academia and industry, and the input of overseas returnees. Together with an increasing focus of the government and domestic enterprises on independent innovation, such developments have enabled China to catch up with the global biotechnology industry. However, its small scale and low capacity for commercializing innovations under China ＂s current regulations and other barriers pose challenges for the development of the industry. Suggestions for the sustainable development of China＇s biotechnology industry are presented in this study.

A SARS-CoV-2 antibody retains potent neutralization against Omicron by targeting conserved RBM residues

The newly emerged Omicron(B.1.1.529)variant of SARS-CoV-2 is quickly overtaking the Delta variant and becoming the dominant strain around the world due to its enhanced transmissibility and high immune escape potential[1,2].Compared to the Wuhan strain,the Omicron variant carries 37 spike mutations,of which 15 are within the receptor-binding domain(RBD)(Fig.1A).A high mutation rate is associated with remarkable resistance to current vaccines and RBD-specific antibody therapeutics[2,3,4].

Junctional and somatic hypermutation-induced CX4C motif is critical for the recognition of a highly conserved epitope on HCV E2 by a human broadly neutralizing antibody

Induction of broadly neutralizing monoclonal antibodies(bNAbs)that bind to the viral envelope glycoproteins is a major goal of hepatitis C virus(HCV)vaccine research.The study of bNAbs arising in natural infection is essential in this endeavor.We generated a human antibody,8D6,recognizing the E2 protein of HCV isolated from a chronic hepatitis C patient.This antibody shows broadly neutralizing activity,which covers a pan-genotypic panel of cell culture-derived HCV virions(HCVcc).Functional and epitope analyses demonstrated that 8D6 can block the interaction between E2 and CD81 by targeting a highly conserved epitope on E2.We describe how the 8D6 lineage evolved via somatic hypermutation to achieve broad neutralization.We found that the V(D)J recombination-generated junctional and somatic hypermutation-induced disulfide bridge(C-C)motif in the CDRH3 is critical for the broad neutralization and binding activity of 8D6.This motif is conserved among a series of broadly neutralizing HCV antibodies,indicating a common binding model.Next,the 8D6 inferred germline(iGL)was reconstructed and tested for its binding affinity and neutralization activity.Interestingly,8D6 iGL-mediated relatively strong inhibition of the 1b genotype PR79L9 strain,suggesting that PR79L9 may serve as a potential natural viral strain that provides E2 sequences that induce bNAbs.Overall,our detailed epitope mapping and genetic studies of the HCV E2-specific mAb 8D6 have allowed for further refinement of antigenic sites on E2 and reveal a new mechanism to generate a functional CDRH3,while its iGL can serve as a probe to identify potential HCV vaccine strains.

Potential contribution of increased soluble IL-2R to lymphopenia in COVID-19 patients

Since the outbreak of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),more than 6 million cases are confirmed and over 300,000 cases are dead after infection.Dysfunction of immunity in COVID-19 patients has been considered as one of the fatal factors for patients,especially cytokine release syndrome and lymphopenia.1,2,3 The reduced number and increased exhaustion level of lymphocyte are associated with elevated inflammatory cytokines in COVID-19 patients.4,5 However,the mechanism of cytokine-induced lymphopenia in COVID-19 is very unclear.IL-2 is critical for the proliferation,differentiation,and function of T cells,including Tregs,CD4+,and CD8+effector cells.6 Here,we reported the negative relationship between the concentration of soluble IL-2 receptor(sIL-2R)and T-cell number in blood from COVID-19 patients.In vitro addition of recombinant CD25 could inhibit the proliferation and function of T cells from PBMC after stimulated with TCR signaling,which could be rescued by strong IL-2 signaling.Our data suggested the importance of IL-2 signaling in lymphopenia of COVID-19 patients.