Oleic acid availability impacts thymocyte preprogramming and subsequent peripheral Treg cell differentiation.

The nature of activation signals is essential in determining T cell subset differentiation; however, the features that determine T cell subset preference acquired during intrathymic development remain elusive. Here we show that naive CD4+ T cells generated in the mouse thymic microenvironment lacking Scd1, encoding the enzyme catalyzing oleic acid (OA) production, exhibit enhanced regulatory T (Treg) cell differentiation and attenuated development of experimental autoimmune encephalomyelitis. Scd1 deletion in K14+ thymic epithelia recapitulated the enhanced Treg cell differentiation phenotype of Scd1-deficient mice. The dearth of OA permitted DOT1L to increase H3K79me2 levels at the Atp2a2 locus of thymocytes at the DN2-DN3 transition stage. Such epigenetic modification persisted in naive CD4+ T cells and facilitated Atp2a2 expression. Upon T cell receptor activation, ATP2A2 enhanced the activity of the calcium-NFAT1-Foxp3 axis to promote naive CD4+ T cells to differentiate into Treg cells. Therefore, OA availability is critical for preprogramming thymocytes with Treg cell differentiation propensities in the periphery.

MHC class Ib-restricted CD8+ T cells possess strong tumoricidal activities.

The importance of classical CD8+ T cells in tumor eradication is well acknowledged. However, the anti-tumor activity of MHC (major histocompatibility complex) Ib-restricted CD8+ T (Ib-CD8+ T) cells remains obscure. Here, we show that CX3CR1-expressing Ib-CD8+ T cells (Ib-restricted CD8+ T cells) highly express cytotoxic factors, austerely resist exhaustion, and effectively eliminate various tumors. These Ib-CD8+ T cells can be primed by MHC Ia (MHC class Ia molecules) expressed on various cell types for optimal activation in a Tbet-dependent manner. Importantly, MHC Ia does not allogeneically activate Ib-CD8+ T cells, rather, sensitizes these cells for T cell receptor activation. Such effects were observed when MHC Ia+ cells were administered to tumor-bearing Kb-/-Db-/-mice. A similar population of tumoricidal CX3CR1+CD8+ T cells was identified in wild-type mice and melanoma patients. Adoptive transfer of Ib-CD8+ T cells to wild-type mice inhibited tumor progression without damaging normal tissues. Taken together, we demonstrate that MHC class Ia can prime Ib-CD8+ T cells for robust tumoricidal activities.

Glycolytic neutrophils accrued in the spleen compromise anti-tumour T cell immunity in breast cancer.

The coordination of immunity across organs is fundamental to cancer development and progression. It is well known that the hostile metabolic microenvironment in the tumour is a major obstacle to effective anti-tumour immunity. However, whether metabolic alterations in secondary lymphoid tissues beyond the tumour can affect anti-tumour immunity remains elusive. Using positron-emission tomography-computed tomography, we show that the spleens of humans and mice with breast cancer are metabolically reprogrammed to a glycolytic state. Such an increase in glucose consumption in the spleen primarily occurs in neutrophils generated by extramedullary haematopoiesis and recruitment from the bone marrow. These neutrophils in the white pulp create a glucose-deprived microenvironment, which, in turn, induces T cell anergy by impairing pyruvate kinase M2 and its action on STAT5, thus compromising their anti-tumour activities. Furthermore, CCL9 chemokine produced by splenic stromal cells is central to splenic neutrophil accumulation, and blockade of the CCR1 receptor favours tumour eradication. Thus, neutrophils metabolically influence the spleen microenvironment and control anti-tumour T cell responses.

SCD1 Sustains Homeostasis of Bulge Niche via Maintaining Hemidesmosomes in Basal Keratinocytes.

Niche for stem cells profoundly influences their maintenance and fate during tissue homeostasis and pathological disorders; however, the underlying mechanisms and tissue-specific features remain poorly understood. Here, it is reported that fatty acid desaturation catabolized by stearoyl-coenzyme A desaturase 1 (SCD1) regulates hair follicle stem cells (HFSCs) and hair growth by maintaining the bulge, niche for HFSCs. Scd1 deletion in mice results in abnormal hair growth, an effect exerted directly on keratin K14+ keratinocytes rather than on HFSCs. Mechanistically, Scd1 deficiency impairs the level of integrin α6ß4 complex and thus the assembly of hemidesmosomes (HDs). The disruption of HDs allows the aberrant activation of focal adhesion kinase and PI3K in K14+ keratinocytes and subsequently their differentiation and proliferation. The overgrowth of basal keratinocytes results in downward extension of the outer root sheath and interruption of bulge formation. Then, inhibition of PI3K signaling in Scd1-/- mice normalizes the bulge, HFSCs, and hair growth. Additionally, supplementation of oleic acid to Scd1-/- mice reestablishes HDs and the homeostasis of bulge niche, and restores hair growth. Thus, SCD1 is critical in regulating hair growth through stabilizing HDs in basal keratinocytes and thus sustaining bulge for HFSC residence and periodic activity.

LDL receptor-related protein 1 (LRP1), a novel target for opening the blood-labyrinth barrier (BLB).

Inner ear disorders are a cluster of diseases that cause hearing loss in more than 1.5 billion people worldwide. However, the presence of the blood-labyrinth barrier (BLB) on the surface of the inner ear capillaries greatly hinders the effectiveness of systemic drugs for prevention and intervention due to the low permeability, which restricts the entry of most drug compounds from the bloodstream into the inner ear tissue. Here, we report the finding of a novel receptor, low-density lipoprotein receptor-related protein 1 (LRP1), that is expressed on the BLB, as a potential target for shuttling therapeutics across this barrier. As a proof-of-concept, we developed an LRP1-binding peptide, IETP2, and covalently conjugated a series of model small-molecule compounds to it, including potential drugs and imaging agents. All compounds were successfully delivered into the inner ear and inner ear lymph, indicating that targeting the receptor LRP1 is a promising strategy to enhance the permeability of the BLB. The discovery of the receptor LRP1 will illuminate developing strategies for crossing the BLB and for improving systemic drug delivery for inner ear disorders.

Heterogeneity of tyrosine-based melanin anabolism regulates pulmonary and cerebral organotropic colonization microenvironment of melanoma cells.

Background: Dietary tyrosine regulating melanoma progression has been well-recognized. However, whether tyrosine-based melanin anabolism contributes to pulmonary and cerebral organotropic colonization of melanoma remains elusive. Furthermore, approaches based on targeting tyrosinase activity to inhibiting multi-organ metastasis of melanoma cells need to be designed and validated. Methods: Patients derived melanoma cells and mouse B16 melanoma cells with different pigmentation were employed in this investigation. Tyrosine content dynamics in tumors and multiple organs during the melanoma progression was monitored, and tyrosine-based melanin synthesis of melanoma cells derived from multi-organ was determined. Additionally, we also adopted RNA-seq, flow cytometry, real-time PCR and composite metastasis mouse model to analyze organotropic colonization and to validate designed therapeutic strategies. Results: B16 melanoma cells with high activity of tyrosinase and sensitivity of tyrosine utilization for melanin synthesis (Tyr-H cells) easily colonized in the lung, while B16 melanoma cells lacking above characteristics (Tyr-L cells) exhibited potent proliferation in the brain. Mechanistically, Tyr-H cells recruited and trained neutrophils and macrophages to establish pulmonary metastatic niche dependent on highly secreted CXCL1 and CXCL2 and an excessive melanosome accumulation-induced cell death. Tyr-L cells enhanced PD-L1 expression in tumor-infiltrated macrophages when they are progressing in the brain. Accordingly, intervention of tyrosinase activity (2-Ethoxybenzamide or hydroquinone) in combination with inhibitors of phagocytosis (GSK343) or chemotaxis (SB225002) suppressed organotropic colonization and significantly improved the survival of melanoma- bearing mice treated with immune checkpoint blockade (PD1 antibody). Conclusions: The heterogeneity of melanoma cells in utilization of tyrosine is associated with organotropic colonization, providing the basis for developing new strategies to combat melanoma.

A Porcine Congenital Single-Sided Deafness Model, Its Population Statistics and Degenerative Changes.

OBJECTIVE: To describe and study the population statistics, hearing phenotype, and pathological changes of a porcine congenital single-sided deafness (CSSD) pedigree. METHODS: Click auditory brainstem response (ABR), full-frequency ABR, and distortion product otoacoustic emission (DPOAE) were used to assess the hearing phenotype of the strain. Tympanogram was used to assess the middle ear function since birth. Celloidin embedding-hematoxylin-eosin (CE-HE) stain and scanning electron microscopy (SEM) were used to study the pathological changes of cochlear microstructures. Chi-square analysis was used to analyze the relation between hearing loss and other phenotypes. RESULTS: The mating mood of CSSD with CSSD was most efficient in breeding-targeted CSSD phenotype (47.62%), and the prevalence of CSSD reached 46.67% till the fifth generation, where 42.22% were bilateral hearing loss (BHL) and 9.00% were normal hearing (NH) individuals. Hearing loss was proved to have no relation with coat color (P = 0.0841 > 0.05) and gender (P = 0.4621 > 0.05) by chi-square analysis. The deaf side of CSSD offspring in the fifth generation had no relation with that of their maternal parent (P = 0.2387 > 0.05). All individuals in this strain exhibited congenital severe to profound sensorineural hearing loss with no malformation and dysfunction of the middle ear. The good hearing ear of CSSD stayed stable over age. The deaf side of CSSD and BHL presented cochlear and saccular degeneration, and the hair cell exhibited malformation since birth and degenerated from the apex to base turn through time. The pathology in BHL cochlea progressed more rapidly than CSSD and till P30, the hair cell had been totally gone. The stria vascularis (SV) was normal since birth and degenerated through time and finally exhibited disorganization of three layers of cells. CONCLUSION: This inbred porcine strain exhibited high and stable prevalence of CSSD, which highly resembled human non-syndromic CSSD disease. This porcine model could be used to further explore the etiology of CSSD and serve as an ideal tool for the studies of the effects of single-sided hearing deprivation on neural, cognitive, and behavioral developments and the benefits brought by CI in CSSD individuals.

[The discussion on the application of simultaneous balloon Eustachian tuboplasty in the hearing reconstruction in patients with chronic suppurative otitis media].

Objective:To explore the application of simultaneous balloon Eustachian tuboplasty（BET） in hearing reconstruction in patients with chronic suppurative otitis media. Method:Twenty-three patients（23ears） who diagnosesd as chronic suppurative otitis media and Eustachian tube dysfunction and underwent hearing reconstruction surgery were retrospectively enrolled, including 12 patients（12 ears） received BET + hearing reconstruction surgery as the case group, 11 patients（11 ears） received hearing reconstruction surgery as the control group. All patients underwent Eustachian tube function score（ETS） and pure tone audiometry before the surgery and one year after the surgery. The subjective improvement degree of symptoms such as ear fullness, muffled hearing, tinnitus and hearing loss were investigated. The differences in test results between the two groups were analyzed. Result:There was no statistically significant difference in ETS and pure tone audiometry between the two groups before the surgery（P>0.05）. The preoperative ETS and postoperative ETS of the case group were 3.75±2.42 and 6.58±2.19, compared to 3.18±1.99 and 4.27±1.79 of the control group. ETS of two groups were improved after surgery（P<0.01）, and the improvement degree of the case group was better than that of the control group（P<0.05）. The preoperative air conduction hearing threshold, bone conduction hearing threshold and air bone gap of the case group were（65.17±11.56） dB, （24.25±12.96） dB, （40.92±12.17） dB, and decreased to（30.58±6.40） dB, （23.67±9.74） dB, and（6.92±12.00） dB after surgery. The preoperative air conduction hearing threshold, bone conduction hearing threshold and air bone gap of the control group were（63.55±9.74） dB, （22.64±8.61） dB, （40.91±9.83） dB, and decreased to （41.45±15.50） dB, （25.73±8.52） dB, （15.73±11.20） dB after surgery. The air conduction hearing threshold and air bone gap of the two groups were improved after surgery（P<0.01）, and the postoperative air conduction threshold of the case group was significantly lower than that of the control group（P<0.05）. In the follow-up questionnaire results, the subjective improvement degree of ear fullness, muffled hearing and hearing loss in the case group was higher than that of the control group（P<0.05）. Conclusion:In patients with chronic suppurative otitis media and Eustachian tube dysfunction, simultaneous BET and hearing reconstruction surgery can effectively increase the patients' hearing improvement degree, and can improve the Eustachian tube function and subjective symptoms.

KIT gene mutation causes deafness and hypopigmentation in Bama miniature pigs.

Waardenburg syndrome (WS) is a common syndromic hearing loss disease. A large group of patients affected by WS were found no mutations in the existed gene panel, indicating that there are still potential genes responsible for WS yet to be detected. In our previous study, we established an autosomal-dominant KIT (OMIM# 164920) mutation (c.2418T>A, p.Asp806Glu) pig pedigree which presented congenital bilateral severe sensorineural hearing loss and hypopigmentation, exact the same as human WS. Histological analysis showed nearly normal structures of the organ of Corti, stria vascularis (SV) and spiral neuron ganglions at E85. Scanning electron microscopy (SEM) exhibited that hair cells started to degenerate at E100, and totally gone at P1. Transmission electron microscope (TEM) showed disorganization of SV and disappearance of intermediate cells. The absence of endocochlear potentials also demonstrated the dysfunction of stria. Our study demonstrated that KIT mutation (c.2418T>A, p.Asp806Glu) interrupted the development of melanocytes in cochlea, which led to SV malformation and dysfunction, resulting in degeneration of hair cells and finally hearing loss. Therefore, KIT was highly supposed to be a newly found gene associated with WS and be added to the WS related gene screening panel clinically.

Scd1 controls de novo beige fat biogenesis through succinate-dependent regulation of mitochondrial complex II.

Preadipocytes can give rise to either white adipocytes or beige adipocytes. Owing to their distinct abilities in nutrient storage and energy expenditure, strategies that specifically promote "beiging" of adipocytes hold great promise for counterbalancing obesity and metabolic diseases. Yet, factors dictating the differentiation fate of adipocyte progenitors remain to be elucidated. We found that stearoyl-coenzyme A desaturase 1 (Scd1)-deficient mice, which resist metabolic stress, possess augmentation in beige adipocytes under basal conditions. Deletion of Scd1 in mature adipocytes expressing Fabp4 or Ucp1 did not affect thermogenesis in mice. Rather, Scd1 deficiency shifted the differentiation fate of preadipocytes from white adipogenesis to beige adipogenesis. Such effects are dependent on succinate accumulation in adipocyte progenitors, which fuels mitochondrial complex II activity. Suppression of mitochondrial complex II by Atpenin A5 or oxaloacetic acid reverted the differentiation potential of Scd1-deficient preadipocytes to white adipocytes. Furthermore, supplementation of succinate was found to increase beige adipocyte differentiation both in vitro and in vivo. Our data reveal an unappreciated role of Scd1 in determining the cell fate of adipocyte progenitors through succinate-dependent regulation of mitochondrial complex II.