Glia maturation factor-γ is involved in S1P-induced marginal zone B-cell chemotaxis and optimal IgM production to type II T-independent antigen.

Marginal zone B cells (MZBs) represent a unique B-cell sub-population that rapidly differentiate into IgM-secreting plasma cells in response to T-independent (T-I) antigen. Sphingosine 1-phosphate (S1P) promotes MZB localization to the marginal zone. However, intracellular molecules involved in MZB localization and migration remain largely unknown. Here, we show that MZBs lacking the glia maturation factor-γ (GMFG) are impaired in chemotaxis toward S1P under both in vitro and in vivo conditions, suggesting that GMFG is an effector downstream of S1P receptors. GMFG undergoes serine phosphorylation upon S1P stimulation and is required for S1P-induced desensitization of S1P receptor 1 (S1PR1). Compared with wild-type mice, Gmfg-/- mice produce elevated levels of 4-hydroxy-3-nitrophenyl-acetyl (NP)-specific IgM against a T-I type II antigen, NP-Ficoll, accompanied by dysregulated MZB localization. These results identify GMFG as a regulator of S1P-induced MZB chemotaxis and reveal a role for MZB localization in the marginal zone for optimal IgM production against a T-I antigen.

MZB1 promotes the secretion of J-chain-containing dimeric IgA and is critical for the suppression of gut inflammation.

IgA is the most abundantly produced antibody in the body and plays a crucial role in gut homeostasis and mucosal immunity. IgA forms a dimer that covalently associates with the joining (J) chain, which is essential for IgA transport into the mucosa. Here, we demonstrate that the marginal zone B and B-1 cell-specific protein (MZB1) interacts with IgA through the α-heavy-chain tailpiece dependent on the penultimate cysteine residue and prevents the intracellular degradation of α-light-chain complexes. Moreover, MZB1 promotes J-chain binding to IgA and the secretion of dimeric IgA. MZB1-deficient mice are impaired in secreting large amounts of IgA into the gut in response to acute inflammation and develop severe colitis. Oral administration of a monoclonal IgA significantly ameliorated the colitis, accompanied by normalization of the gut microbiota composition. The present study identifies a molecular chaperone that promotes J-chain binding to IgA and reveals an important mechanism that controls the quantity, quality, and function of IgA.

Efficient and Reliable MicroRNA Imaging in Living Cells via a FRET-Based Localized Hairpin-DNA Cascade Amplifier.

MicroRNAs (miRNAs) play critical roles in many biological processes and are vital biomarkers for disease diagnostics. Hence, it is of significance to develop miRNA biosensors with fast responses, high sensitivity, and excellent reliability in living cells. As one kind of DNA molecular machine, DNA amplifiers are very promising for intracellular miRNA imaging due to their nonenzymatic, isothermal working principle and excellent signal-amplification ability. However, the practical application of current DNA amplifiers is still an issue because of their slow kinetics, unsatisfactory efficiency, and false-positive signals. Herein, taking advantage of the spatial-confinement effect on a three-dimensional (3D) finite DNA nanostructure, a FRET-based localized hairpin-DNA cascade amplifier (termed as localized-HDCA) is developed for the rapid, efficient, and reliable imaging of intracellular tumor-related miRNA. The localized-HDCA system consists of two metastable hairpin DNAs (H1 and H2) localized on a DNA nanocube. Benefiting from the spatial-confinement effect in the confined space of DNA nanocubes, not only was the speed of the miRNA-triggered HDCA reaction significantly accelerated (7 times faster), but also the reaction efficiency was greatly improved (2.6 times higher). In addition, the FRET-based 3D finite DNA nanocubes provide this localized-HDCA with improved cell permeability and better nuclease resistance as well as the ability to avoid false-positive signals, which guarantee reliable miRNA imaging in living cells. With these advantages, this strategy is expected to be widely applied to the development of more efficient and robust DNA molecular machines for biomedical research and clinical diagnosis.

FcµR interacts and cooperates with the B cell receptor To promote B cell survival.

The IgM FcR (FcµR) promotes B cell survival, but the molecular mechanism remains largely unknown. We show using FcµR(-/-) and wild-type mice that FcµR specifically enhanced B cell survival induced by BCR cross-linking with F(ab')2-anti-IgM Abs while having no effect on survival when the B cells were activated by CD40 ligation or LPS stimulation. FcµR expression was markedly upregulated by anti-IgM stimulation, which may promote enhanced FcµR signaling in these cells. Immunofluorescence and confocal microscopy analyses demonstrated that FcµR colocalized with the BCR on the plasma membrane of primary B cells. Coimmunoprecipitation analysis further revealed that FcµR physically interacted with the BCR complex. Because NF-κB plays a prominent role in B cell survival, we analyzed whether FcµR was involved in BCR-triggered NF-κB activation. FcµR did not affect BCR-triggered IκBα phosphorylation characteristic of the canonical NF-κB activation pathway but promoted the production of the noncanonical NF-κB pathway component p52. Consistent with the elevated p52 levels, FcµR enhanced BCR-triggered expression of the antiapoptotic protein BCL-xL. Importantly, FcµR stimulation alone in the absence of BCR signaling had no effect on either IκBα phosphorylation or the expression of p52 and BCL-xL. Therefore, FcµR relied on the BCR signal to activate the noncanonical NF-κB pathway and enhance B cell survival. These results reveal a cross-talk downstream of FcµR and BCR signaling and provide mechanistic insight into FcµR-mediated enhancement of B cell survival after BCR stimulation.

HSP90α deficiency does not affect immunoglobulin gene hypermutation and class switch but causes enhanced MHC class II antigen presentation.

Heat shock protein 90 (HSP90) is a molecular chaperone required for efficient antigen presentation and cross-presentation. In addition, HSP90 was recently reported to interact with and stabilize the activation-induced cytidine deaminase (AID) and plays a critical role in immunoglobulin gene hypermutation and class switch recombination. In mice and humans, there are two HSP90 isoforms, HSP90α and HSP90ß, but the in vivo role of each isoform remains largely unknown. Here we have analyzed humoral immune responses in HSP90α-deficient mice. We found that HSP90α deficiency did not affect AID protein expression. B cell development and maturation, as well as immunoglobulin gene hypermuation and class switch, occurred normally in HSP90α-deficient mice. However, antibody production to a T-dependent antigen was elevated in the mutant mice and this was associated with enhanced MHC class II antigen presentation to T helper cells by dendritic cells. Our results reveal a previously unidentified inhibitory role for HSP90α isoform in MHC class II antigen presentation and the humoral immune response. Along with our recent finding that HSP90α is required for antigen cross-presentation, these results suggest that HSP90α controls the balance of humoral and cellular immunity by dictating the fate of presentation of exogenous antigen.

Suppressing DNMT3a Alleviates the Intrinsic Epigenetic Barrier for Optic Nerve Regeneration and Restores Vision in Adult Mice.

The limited regenerative potential of the optic nerve in adult mammals presents a major challenge for restoring vision after optic nerve trauma or disease. The mechanisms of this regenerative failure are not fully understood1,2. Here, through small-molecule and genetic screening for epigenetic modulators3, we identify DNA methyltransferase 3a (DNMT3a) as a potent inhibitor of axon regeneration in mouse and human retinal explants. Selective suppression of DNMT3a in retinal ganglion cells (RGCs) by gene targeting or delivery of shRNA leads to robust, full-length regeneration of RGC axons through the optic nerve and restoration of vision in adult mice after nerve crush injury. Genome-wide bisulfite and transcriptome profiling in combination with single nucleus RNA-sequencing of RGCs revealed selective DNA demethylation and reactivation of genetic programs supporting neuronal survival and axonal growth/regeneration by DNMT3a deficiency. This was accompanied by the suppression of gene networks associated with apoptosis and inflammation. Our results identify DNMT3a as the central orchestrator of an RGC-intrinsic mechanism that limits optic nerve regeneration. Suppressing DNMT3a expression in RGCs unlocks the epigenetic switch for optic nerve regeneration and presents a promising therapeutic avenue for effectively reversing vision loss resulted from optic nerve trauma or diseases.

A T cell receptor targeting a recurrent driver mutation in FLT3 mediates elimination of primary human acute myeloid leukemia in vivo.

Acute myeloid leukemia (AML), the most frequent leukemia in adults, is driven by recurrent somatically acquired genetic lesions in a restricted number of genes. Treatment with tyrosine kinase inhibitors has demonstrated that targeting of prevalent FMS-related receptor tyrosine kinase 3 (FLT3) gain-of-function mutations can provide significant survival benefits for patients, although the efficacy of FLT3 inhibitors in eliminating FLT3-mutated clones is variable. We identified a T cell receptor (TCR) reactive to the recurrent D835Y driver mutation in the FLT3 tyrosine kinase domain (TCRFLT3D/Y). TCRFLT3D/Y-redirected T cells selectively eliminated primary human AML cells harboring the FLT3D835Y mutation in vitro and in vivo. TCRFLT3D/Y cells rejected both CD34+ and CD34- AML in mice engrafted with primary leukemia from patients, reaching minimal residual disease-negative levels, and eliminated primary CD34+ AML leukemia-propagating cells in vivo. Thus, T cells targeting a single shared mutation can provide efficient immunotherapy toward selective elimination of clonally involved primary AML cells in vivo.

Comparison of two POLQ mutants reveals that a polymerase-inactive POLQ retains significant function in tolerance to etoposide and γ-irradiation in mouse B cells.

DNA polymerase θ (POLQ) is a family A polymerase that contains an intrinsic helicase domain. POLQ has been implicated in tolerance to DNA damage but whether this depends solely on its polymerase domain remains unknown. In this study, we generated POLQ-null CH12F3 B cells by gene targeting and compared their sensitivity to DNA-damaging agents with previously established POLQ-inactive CH12F3 cells in which only the polymerase core domain was deleted. Compared with WT cells, POLQ-null and POLQ-inactive cells exhibited similarly increased sensitivity to mitomycin C, cisplatin, and ultraviolet radiation, suggesting that tolerance to these DNA-damaging agents depends largely on POLQ polymerase activity. Intriguingly, POLQ-null cells exhibited higher sensitivity than did POLQ-inactive cells to etoposide and γ-irradiation, both of which induce double-strand breaks (DSBs). This observation indicates that the polymerase-deleted POLQ, expressed in POLQ-inactive cells, retains significant function in tolerance to these agents. Class switch recombination of immunoglobulin genes, which involves repair of activation-induced cytidine deaminase (AID)-triggered DSBs, however, was unaffected in both POLQ-null and POLQ-inactive cells. These results suggest that the polymerase and other functional domains of POLQ both play important roles in tolerance to etoposide and γ-irradiation but are dispensable for AID-mediated class switch recombination.

A Pharmacoinformatics Analysis of Artemisinin Targets and de novo Design of Hits for Treating Ulcerative Colitis.

Ulcerative colitis (UC), as an intractably treated disease, seriously affects the quality of life of patients and has an increase in terms of incidence and prevalence annually. However, due to the lack of a direct etiology and drug-induced side effects, the medical treatment of UC falls into a bottleneck. There are many natural phytochemicals with the potential to regulate immune function in nature. Herein, a potential mechanism of artemisinin in the treatment of UC and potential druggability compounds with an artemisinin peroxide bond were discussed and predicted based on computer-aided drug design (CADD) technology by using the methods of network pharmacology, molecular docking, de novo drug structure design and molecular dynamics through the integration of artemisinin related targets from TCMSP, ChEMBL and HERB databases. The networks were constructed based on 50 artemisinin-disease intersection targets related to inflammation, cytokines, proliferation and apoptosis, showing the importance of GALNT2, BMP7 and TGFBR2 in the treatment of disease, which may be due to the occupation of the ricin B-type lectin domain of GALNT2 by artemisinin compounds or de novo designed candidates. This result could guide the direction of experiments and actual case studies in the future. This study provides a new route for the application of artemisinin and the development of drugs.

Neck-to-height ratio is positively associated with diabetic kidney disease in Chinese patients with type 2 diabetes mellitus.

Introduction: The aim of this study was to investigate the associations of neck circumference (NC) and neck-to-height (NHR) with diabetic kidney disease (DKD) in Chinese patients with type 2 diabetes mellitus (T2DM). Materials and methods: A total of 2,615 patients with prevalent T2DM were enrolled. NHR was calculated through NC (cm) divided by height (cm), and prevalent DKD was defined as the urinary albumin-to-creatinine ratio (UACR) ≥ 30 mg/g or the estimated glomerular filtration rate (eGFR) < 60 ml/min per 1.73 m2 in the absence of other primary kidney diseases. Results: The levels of NC and NHR were higher in DKD patients compared with non-DKD patients (38.22 vs. 37.71, P = 0.003; 0.232 vs. 0.227, P < 0.001, respectively). After full adjustments, individuals at the highest tertile of NHR had higher odds of DKD than those at the lowest tertile (multivariate-adjusted OR = 1.63, 95% CI: 1.22, 2.18), but this association was not pronounced with NC (multivariate-adjusted OR = 1.24, 95% CI: 0.87, 1.76). Individuals at the highest tertile of NHR had lower eGFR (ß = -4.64, 95% CI: -6.55, -2.74) and higher UACR levels (ß = 0.27, 95% CI: 0.10, 0.45) than those at the lowest tertile. The adverse association between NHR and prevalent DKD remained statistically significant among most of the subgroups analyzed and no interaction effects were observed. Conclusion: The increase in NHR was adversely and independently associated with DKD in this Chinese T2DM population.

Inverse Association of Fruit and Vegetable Consumption with Nonalcoholic Fatty Liver Disease in Chinese Patients with Type 2 Diabetes Mellitus.

We aimed to investigate the association of fruit and vegetable consumption with nonalcoholic fatty liver disease (NAFLD) in Chinese patients with type 2 diabetes mellitus (T2DM). This cross-sectional study included 2667 Chinese patients with T2DM aged 18 to 76 years from March 2017 to October 2021. Dietary intake was assessed using a food frequency questionnaire, and prevalent NAFLD was diagnosed with abdominal ultrasonography. High fruit−vegetable consumption was determined using ≥500 g/day consumption of both fruit and vegetable, and both fruit and vegetable consumption were divided into three categories of <200 g/day (low), 200−400 g/day (median) and >400 g (high). The primary outcome measurement was multivariate-adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for the prevalence of NAFLD in relation to the highest fruit and (or) vegetable intake compared with the lowest. Secondary analyses were conducted to assess the effects of either fruit or vegetable intake on the fatty liver index (FLI) using multivariable linear regressions. There were 1694 men and 973 women in this study, and 1445 (54.06%) participants had prevalent NAFLD. Patients with high fruit−vegetable intake had a lower prevalence of NAFLD than those with low fruit−vegetable intake (52.04% vs. 56.48%), but this difference was not statistically significant (p = 0.065). Vegetable intake had a significantly inverse association with NAFLD (OR: 0.68, 95% CI: 0.52−0.90), but this association was not pronounced with fruit intake (OR: 1.23, 95% CI: 0.89−1.69) or fruit−vegetable intake (OR: 0.90, 95% CI: 0.73−1.10). Additional analyses showed that an increase in vegetable intake was linearly associated with a significant reduction in FLI (ß: −1.028, 95% CI: −1.836, −0.219). In conclusion, higher vegetable consumption was associated with lower odds of NAFLD in Chinese patients with T2DM, which suggested that increased vegetable intake might protect patients with diabetes against NAFLD.

The Association of Sarcopenia and Visceral Obesity with Lean Nonalcoholic Fatty Liver Disease in Chinese Patients with Type 2 Diabetes Mellitus.

Background: Few studies have specifically observed the relationship of sarcopenia, visceral obesity, or their joint effects with lean NAFLD in patients with diabetes. We aimed to investigate the associations of lean NAFLD with sarcopenia, visceral obesity, and sarcopenic visceral obesity (SV) in Chinese patients with type 2 diabetes mellitus (T2DM). Methods: Altogether, 1,112 T2DM patients with BMI <25 kg/m2 were enrolled, and 33.18% of them were diagnosed with lean NAFLD by abdominal ultrasonography. Body composition markers were measured by bioelectrical impedance (BIA). Skeletal muscle mass index (SMI) was calculated as appendicular skeletal muscle mass (ASM) divided by weight, and sarcopenia was defined as SMI < 1 standard deviation (SD) below the sex-specific average for a young reference population. Visceral obesity was defined as visceral fat area (VFA) ≥ 100 cm2. Participants were categorized into one of the four body composition groups: nonsarcopenia/nonvisceral obesity (NN), nonsarcopenia/visceral obesity (NV), sarcopenia/nonvisceral obesity (SN), and SV. Results: Compared to those in the NN group, patients in the NV and SN groups had a higher risk of lean NAFLD after full adjustments (NV: OR = 1.74; 95% CI: 1.09, 2.78; SN: OR =2.07; 95% CI: 1.23, 3.46). Of note, patients in the SV group had the highest odds of lean NAFLD (OR = 3.29; 95% CI: 2.10, 5.17). There were no significant interaction effects between sarcopenia and metabolic risk factors on prevalent lean NAFLD. Conclusions: The current study demonstrated that SV was more closely associated with higher prevalent lean NAFLD than sarcopenia or visceral obesity alone in Chinese patients with T2DM. Besides, the harmful effect of sarcopenia on lean NAFLD was not influenced by visceral obesity or other metabolic risk factors. We hypothesize that increasing skeletal muscle mass more than just reducing visceral fat might be more optimal for the prevention and management of lean NAFLD, which needs further investigation in future studies.

T cells targeted to TdT kill leukemic lymphoblasts while sparing normal lymphocytes.

Unlike chimeric antigen receptors, T-cell receptors (TCRs) can recognize intracellular targets presented on human leukocyte antigen (HLA) molecules. Here we demonstrate that T cells expressing TCRs specific for peptides from the intracellular lymphoid-specific enzyme terminal deoxynucleotidyl transferase (TdT), presented in the context of HLA-A*02:01, specifically eliminate primary acute lymphoblastic leukemia (ALL) cells of T- and B-cell origin in vitro and in three mouse models of disseminated B-ALL. By contrast, the treatment spares normal peripheral T- and B-cell repertoires and normal myeloid cells in vitro, and in vivo in humanized mice. TdT is an attractive cancer target as it is highly and homogeneously expressed in 80-94% of B- and T-ALLs, but only transiently expressed during normal lymphoid differentiation, limiting on-target toxicity of TdT-specific T cells. TCR-modified T cells targeting TdT may be a promising immunotherapy for B-ALL and T-ALL that preserves normal lymphocytes.

HnRNP U mediates the long-range regulation of Shh expression during limb development.

Transcriptional modulation may be mediated by cis-regulatory elements distant from their target genes. Mutations in a conserved locus about 1 Mb upstream of the Shh coding region often affect Shh expression and are associated with preaxial polydactyly (PPD) defects. To understand the molecular mechanism, we analyzed a novel mouse PPD model with a T-to-A point mutation in this distant locus. A core element of mutation (CEM) with putative enhancer activity was identified by promoter activity assay and shown to contain a matrix attachment region. HnRNP U preferentially bound to the mutant but not the wild-type CEM. Interestingly, HnRNP U also bound to the 5'-UTR of the Shh gene, which was not located in the nuclear matrix in wild-type embryonic cells, as indicated by chromatin immunoprecipitation. We propose that the 5'-UTR of Shh was pulled into the nuclear matrix by HnRNP U when the CEM was mutated, and consequently affected Shh expression. Therefore, distant cis-elements may modulate gene expression by altering HnRNP U's affinity for certain mediator proteins and nuclear relocation.

A critical role for REV1 in regulating the induction of C:G transitions and A:T mutations during Ig gene hypermutation.

REV1 is a deoxycytidyl transferase that catalyzes the incorporation of deoxycytidines opposite deoxyguanines and abasic sites. To explore the role of its catalytic activity in Ig gene hypermutation in mammalian cells, we have generated mice expressing a catalytically inactive REV1 (REV1AA). REV1AA mice developed normally and were fertile on a pure C57BL/6 genetic background. B and T cell development and maturation were not affected, and REV1AA B cells underwent normal activation and class switch recombination. Analysis of Ig gene hypermutation in REV1AA mice revealed a great decrease of C to G and G to C transversions, consistent with the disruption of its deoxycytidyl transferase activity. Intriguingly, REV1AA mice also exhibited a significant reduction of C to T and G to A transitions. Moreover, each type of nucleotide substitutions at A:T base pairs was uniformly reduced in REV1AA mice, a phenotype similar to that observed in mice haploinsufficient for Polh. These results reveal an unexpected role for REV1 in the generation of C:G transitions and A:T mutations and suggest that REV1 is involved in multiple mutagenic pathways through functional interaction with other polymerases during the hypermutation process.

Phosphate Group-Derivated Bipyridine-Ruthenium Complex and Titanium Dioxide Nanoparticles for Electrochemical Sensing of Protein Kinase Activity.

Monitoring of protein kinase activity is of significance for fundamentals of biochemistry, biomedical diagnose, and drug screening. To reduce the usage of a relatively complicated bio-labeled signal probe, the phosphate group-derivated bipyridine-ruthenium (Pbpy-Ru) complex and titanium dioxide nanoparticles (TiO2 NPs) were employed as signal probes to develop an electrochemical sensor for evaluating the protein kinase A (PKA) activity. Through the specific interaction between the phosphate groups and TiO2 NPs, the preparation of a Pbpy-Ru-TiO2 NP signal probe and its linkage with the phosphorylated PKA substrate peptides could be performed in a simple and effective way. The tethering of Pbpy-Ru onto the TiO2 NP surface does not degrade the electrochemical property of the complex. The Pbpy-Ru-TiO2 NP probe exhibits well-defined redox signals at about 1.0 V versus Ag/AgCl reference and notably has about fivefold current response than that of the TiO2 NPs with physically adsorbed tris-(bipyridine)-Ru. The PKA activity evaluation was realized by measuring the electrochemical response of the Pbpy-Ru-TiO2 NPs at the phosphorylated peptide-assembled electrode. Operating at optimal conditions, the cathodic signals at the potential of 1.03 V exhibit a good linearity with the PKA concentrations of 0.5-40 U mL-1. The electrochemical sensor shows good selectivity, low detection limit (0.2 U mL-1, signal/noise = 3), qualified reproducibility, and satisfactory applicability for PKA determination in the cell lysate. The Pbpy-Ru-TiO2 NPs/electrode system would be an excellent electrochemical platform for protein phosphorylation monitoring and sensing.

Apoptosis induced by methylene-blue-mediated photodynamic therapy in melanomas and the involvement of mitochondrial dysfunction revealed by proteomics.

Methylene blue (MB) is a widely studied agent currently under investigation for its properties relating to photodynamic therapy (PDT). Recent studies have demonstrated that MB exhibits profound phototoxicity affecting a variety of tumor cell lines. However, the mechanistic explanation for methylene-blue-mediated photodynamic therapy (MB-PDT) in the context of melanoma therapy is still obscure. In the present study, B16F1 melanoma cells were treated by MB-PDT under different conditions, and thereafter subjected to cell viability detection assays. MB-PDT could induce intense apoptotic cell death through a series of steps beginning with the photochemical generation of reactive oxygen species that activate the caspase-9/caspase-3 apoptosis pathway. Blocking activation of caspase-3 and induction of oxidative stress by caspase inhibitor and by glutathione, respectively, markedly reduced apoptotic cell death in vitro. Importantly, proteomics study defining altered protein expression in treated cells suggests the involvement of several mitochondrial proteins playing important roles in electron transfer chain, implying mitochondrial dysfunction during the treatment. Furthermore, a transplantable mouse melanoma model was utilized to estimate the effectiveness of MB-PDT in vivo. The treated mice displayed decreased tumor size and prolonged survival days, which was associated with enhanced apoptotic cell death. These results, offering solid evidence of the induction of mitochondria-related apoptosis in tumor cells, reveal new aspects of MB-PDT having potential to be a palliative treatment of melanoma.

IGFBPL1 Regulates Axon Growth through IGF-1-mediated Signaling Cascades.

Activation of axonal growth program is a critical step in successful optic nerve regeneration following injury. Yet the molecular mechanisms that orchestrate this developmental transition are not fully understood. Here we identified a novel regulator, insulin-like growth factor binding protein-like 1 (IGFBPL1), for the growth of retinal ganglion cell (RGC) axons. Expression of IGFBPL1 correlates with RGC axon growth in development, and acute knockdown of IGFBPL1 with shRNA or IGFBPL1 knockout in vivo impaired RGC axon growth. In contrast, administration of IGFBPL1 promoted axon growth. Moreover, IGFBPL1 bound to insulin-like growth factor 1 (IGF-1) and subsequently induced calcium signaling and mammalian target of rapamycin (mTOR) phosphorylation to stimulate axon elongation. Blockage of IGF-1 signaling abolished IGFBPL1-mediated axon growth, and vice versa, IGF-1 required the presence of IGFBPL1 to promote RGC axon growth. These data reveal a novel element in the control of RGC axon growth and suggest an unknown signaling loop in the regulation of the pleiotropic functions of IGF-1. They suggest new therapeutic target for promoting optic nerve and axon regeneration and repair of the central nervous system.

Author Correction: Commensal microflora-induced T cell responses mediate progressive neurodegeneration in glaucoma.

The originally published version of this Article contained an error in Figure 4. The bar chart in panel f was inadvertently replaced with a duplicate of the bar chart in panel e. This error has now corrected in both the PDF and HTML versions of the Article.

Commensal microflora-induced T cell responses mediate progressive neurodegeneration in glaucoma.

Glaucoma is the most prevalent neurodegenerative disease and a leading cause of blindness worldwide. The mechanisms causing glaucomatous neurodegeneration are not fully understood. Here we show, using mice deficient in T and/or B cells and adoptive cell transfer, that transient elevation of intraocular pressure (IOP) is sufficient to induce T-cell infiltration into the retina. This T-cell infiltration leads to a prolonged phase of retinal ganglion cell degeneration that persists after IOP returns to a normal level. Heat shock proteins (HSP) are identified as target antigens of T-cell responses in glaucomatous mice and human glaucoma patients. Furthermore, retina-infiltrating T cells cross-react with human and bacterial HSPs; mice raised in the absence of commensal microflora do not develop glaucomatous T-cell responses or the associated neurodegeneration. These results provide compelling evidence that glaucomatous neurodegeneration is mediated in part by T cells that are pre-sensitized by exposure to commensal microflora.