Follicular helper- and peripheral helper-like T cells drive autoimmune disease in human immune system mice.

Human immune system (HIS) mice constructed in various ways are widely used for investigations of human immune responses to pathogens, transplants and immunotherapies. In HIS mice that generate T cells de novo from hematopoietic progenitors, T cell-dependent multisystem autoimmune disease occurs, most rapidly when the human T cells develop in the native NOD.Cg- Prkdc scid Il2rg tm1Wjl (NSG) mouse thymus, where negative selection is abnormal. Disease develops very late when human T cells develop in human fetal thymus grafts, where robust negative selection is observed. We demonstrate here that PD-1 + CD4 + peripheral (Tph) helper-like and follicular (Tfh) helper-like T cells developing in HIS mice can induce autoimmune disease. Tfh-like cells were more prominent in HIS mice with a mouse thymus, in which the highest levels of IgG were detected in plasma, compared to those with a human thymus. While circulating IgG and IgM antibodies were autoreactive to multiple mouse antigens, in vivo depletion of B cells and antibodies did not delay the development of autoimmune disease. Conversely, adoptive transfer of enriched Tfh- or Tph-like cells induced disease and autoimmunity-associated B cell phenotypes in recipient mice containing autologous human APCs without T cells. T cells from mice with a human thymus expanded and induced disease more rapidly than those originating in a murine thymus, implicating HLA-restricted T cell-APC interactions in this process. Since Tfh, Tph, autoantibodies and LIP have all been implicated in various forms of human autoimmune disease, the observations here provide a platform for the further dissection of human autoimmune disease mechanisms and therapies.

Long-Term Effects and Prognosis Following Suction Blister Epidermal Grafting in Vitiligo Patients.

BACKGROUND: Suction blister epidermal grafting (SBEG) is currently one of the most prevalent surgical methods for stable vitiligo. OBJECTIVE: To investigate the long-term outcomes of vitiligo patients who underwent SBEG and to explore risk factors associated with postoperative relapse. METHODS: A retrospective cohort study was conducted in patients who underwent SBEG in our department between January 2016 and December 2022. Treatment outcomes, including repigmentation rate, adverse events, and postoperative relapse, were surveyed via telephone interview or out-=patient visit. Multivariate logistic regression models were used to assess the potential risk factors for postoperative relapse. Statistical significance was assumed at P < .05. RESULTS: A total of 253 patients were included with a repigmentation rate of 96% (243/253) after grafting. Common adverse events included cobblestone-like appearance (73.1%, 185/253) in the donor site, perigraft halo (46.2%, 117/253), and cobblestone-like appearance (26.1%, 66/253) in the recipient site. Postoperative relapse occurred in 20.1% of patients over a mean time of 29.7 months after grafting. Nonsegmental type of vitiligo and coexistence of autoimmune diseases were risk factors for postoperative relapse. CONCLUSION: SBEG is an effective surgical treatment for vitiligo with high repigmentation rate and good safety profile. Nonsegmental vitiligo and comorbid autoimmune diseases may increase the risk of postoperative relapse.

Origin, phenotype and autoimmune potential of T cells in human immune system mice receiving neonatal human thymus tissue.

Robust human immune system (HIS) mice are created using human fetal thymus tissue and hematopoietic stem cells (HSCs). A HIS mouse model using neonatal human thymus tissue and umbilical cord blood (CB) HSCs (NeoHu) was recently described. We improved the model by removing the native murine thymus, which can also generate human T cells, and demonstrated definitively the capacity of human T cells to develop in a grafted neonatal human thymus. Human T cells derived from the neonatal thymus tissue appeared in peripheral blood early post-transplantation and CB-derived T cells appeared later. Naïve T cells were demonstrated in peripheral blood but effector memory and T peripheral helper phenotypes predominated later, in association with development of autoimmunity in some animals. Treatment of thymus grafts with 2-deoxyglucose (2-DG) increased the proportion of stem cells derived from injected HSCs, delayed onset of autoimmune disease, reduced early T cell reconstitution, and reduced effector/memory T cell conversion. Younger neonatal human thymus tissue was associated with improved T cell reconstitution. While the NeoHu model bypasses the need for fetal tissue, it has yet to demonstrate equivalent reconstitution to fetal tissue, though 2-DG can improve results by removing native thymocytes prior to transplantation.

Ultrathin Skin Grafting Versus Suction Blister Epidermal Grafting in the Treatment of Resistant Stable Vitiligo: A Self-Controlled Comparative Study.

BACKGROUND: Surgical therapies are effective methods to treat resistant stable vitiligo, with each method having advantages and disadvantages. OBJECTIVE: This study aimed to compare the efficacy and safety of ultrathin skin grafting (UTSG) and suction blister epidermal grafting (SBEG) to treat stable vitiligo. METHODS: A total of 15 patients with 45 vitiligo patches were recruited. Each vitiligo patch was divided in half; 1 half was treated by UTSG, whereas the other half was treated by SBEG. The patients were followed up monthly for 3 months to assess the repigmentation rate, relative melanin index (RMI), and relative erythema index (REI) at different timepoints. RESULTS: Excellent repigmentation was observed in 97.8% of patches that underwent UTSG and 93.3% that underwent SBEG. The RMI and REI at 1, 2, and 3 months after the grafting procedure did not significantly differ between the 2 methods. At the recipient site, incomplete fall-off of the graft occurred in 4.4% of patches that underwent UTSG, whereas a "cobblestone appearance" was observed in 66.7% of patches that underwent SEBG. UTSG caused fewer complications at the donor site than SBEG. CONCLUSION: Compared with SBEG, UTSG is faster and achieves better cosmetic outcomes at the recipient and donor sites.

T1D patient-derived hematopoietic stem cells are programmed to generate Tph, Tfh, and autoimmunity-associated B cell subsets in human immune system mice.

Interactions between B cells and CD4+ T cells play a central role in the development of Type 1 Diabetes (T1D). Two helper cell subsets, follicular (Tfh) and peripheral (Tph) helper T cells, are increased in patients with T1D but their role in driving B cell autoimmunity is undefined. We used a personalized immune (PI) mouse model to generate human immune systems de novo from hematopoietic stem cells (HSCs) of patients with T1D or from healthy controls (HCs). Both groups developed Tfh and Tph-like cells, and those with T1D-derived immune systems demonstrated increased numbers of Tph-like and Tfh cells compared to HC-derived PI mice. T1D-derived immune systems included increased proportions of unconventional memory CD27-IgD- B cells and reduced proportions of naïve B cells compared to HC PI mice, resembling changes reported for patients with systemic lupus erythematosus. Our findings suggest that T1D HSCs are genetically programmed to produce increased proportions of T cells that promote the development of unconventional, possibly autoreactive memory B cells. PI mice provide an avenue for further understanding of the immune abnormalities that drive autoantibody pathogenesis and T1D.

Aristolochic acid I promoted clonal expansion but did not induce hepatocellular carcinoma in adult rats.

Aristolochic acid I (AAI) is a well-known nephrotoxic carcinogen, which is currently reported to be also associated with hepatocellular carcinoma (HCC). Whether AAI is a direct hepatocarcinogen remains controversial. In this study we investigated the association between AAI exposure and HCC in adult rats using a sensitive rat liver bioassay with several cofactors. Formation of glutathione S-transferase placental form-positive (GST-P+) foci was used as the marker for preneoplastic lesions/clonal expansion. We first conducted a medium-term (8 weeks) study to investigate whether AAI had any tumor-initiating or -promoting activity. Then a long-term (52 weeks) study was conducted to determine whether AAI can directly induce HCC. We showed that oral administration of single dose of AAI (20, 50, or 100 mg/kg) in combination with partial hepatectomy (PH) to stimulate liver proliferation did not induce typical GST-P+ foci in liver. In the 8-week study, only high dose of AAI (10 mg · kg-1 · d-1, 5 days a week for 6 weeks) in combination with PH significantly increased the number and area of GST-P+ foci initiated by diethylnitrosamine (DEN) in liver. Similarly, only high dose of AAI (10 mg· kg-1· d-1, 5 days a week for 52 weeks) in combination with PH significantly increased the number and area of hepatic GST-P+ foci in the 52-week study. No any nodules or HCC were observed in liver of any AAI-treated groups. In contrast, long-term administration of AAI (0.1, 1, 10 mg· kg-1· d-1) time- and dose-dependently caused death due to the occurrence of cancers in the forestomach, intestine, and/or kidney. Besides, AAI-DNA adducts accumulated in the forestomach, kidney, and liver in a time- and dose-dependent manner. Taken together, AAI promotes clonal expansion only in the high-dose group but did not induce any nodules or HCC in liver of adult rats till their deaths caused by cancers developed in the forestomach, intestine, and/or kidney. Findings from our animal studies will pave the way for further large-scale epidemiological investigation of the associations between AA and HCC.

Role of the thymus in spontaneous development of a multi-organ autoimmune disease in human immune system mice.

We evaluated the role of the thymus in development of multi-organ autoimmunity in human immune system (HIS) mice. T cells were essential for disease development and the same T cell clones with varying phenotypes infiltrated multiple tissues. De novo-generated hematopoietic stem cell (HSC)-derived T cells were the major disease drivers, though thymocytes pre-existing in grafted human thymi contributed if not first depleted. HIS mice with a native mouse thymus developed disease earlier than thymectomized mice with a thymocyte-depleted human thymus graft. Defective structure in the native mouse thymus was associated with impaired negative selection of thymocytes expressing a transgenic TCR recognizing a self-antigen. Disease developed without direct recognition of antigens on recipient mouse MHC. While human thymus grafts had normal structure and negative selection, failure to tolerize human T cells recognizing mouse antigens presented on HLA molecules may explain eventual disease development. These new insights have implications for human autoimmunity and suggest methods of avoiding autoimmunity in next-generation HIS mice.

Ablation of DJ-1 Enhances Oxidative Stress by Disturbing the Function of Mitochondria in Epidermal Melanocytes.

BACKGROUND: Oxidative stress is implicated in the pathogenesis of vitiligo. The function of DJ-1 in oxidative damage of melanocytes is still elusive. AIMS: The aim of this study was to investigate the role of DJ-1 in oxidative damage of melanocytes. MATERIAL AND METHODS: The expression of DJ-1 in melanocytes was studied by reverse transcription-quantitative polymerase chain reaction and Western blot. Short-interfering RNAs (siRNA) were employed to downregulate DJ-1. The cells were pooled into three groups: mock group (cells with transfection reagent), negative control (NC) group (negative siRNA control), and siRNA group. After H2O2 treatment for 24 h, the morphological changes, cell viability, apoptosis, intracellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and mitochondrial respiration were measured in different groups. RESULTS: DJ-1 was highly expressed in PIG1 melanocytes. DJ-1 knockdown rendered PIG1 melanocytes more susceptible to oxidative stress. Loss of DJ-1 led to apoptosis of PIG1 cells by impairing the function of mitochondria, including morphological abnormalities, ROS accumulation, depolarization of MMP, less adenosine-triphosphate (ATP) production, and less proton leak. CONCLUSIONS: DJ-1 plays a role in maintaining the antioxidative capacity in epidermal melanocytes.

[Sporadic cutaneous infections due to nontuberculous mycobacteria: a retrospective study of 37 cases].

OBJECTIVE: To study the clinical and pathological characteristics of sporadic cutaneous infections due to nontuberculous mycobacteria (NTM), and investigate the diagnostic criteria and therapeutic principal. METHODS: Totally 37 cases of sporadic cutaneous infections due to NTM were confirmed in the Department of Dermatology, Peking University People's Hospital from January 2000 to March 2014. The microbiologic and clinical data were reviewed, and their skin biopsy specimens were reassessed. RESULTS: Of all the 37 patients, 30 cases were Mycobacterium marinum infection, 6 were Mycobacterium abscessus infection, and one was Mycobacterium chelonea and Mycobacterium fortuitum infection. Identification of mycobacterial species by analysis of hsp65 gene in tissue DNA was more sensitive than traditional bacterial culture. The most common risk factors were traumatic injuries (21 of 37) and aquarium or fish-related job (21 of 37). One case of Mycobacterium abscessus infection occurred after autologous fat filling. Nodule and plaque were most common lesions in Mycobacterium marinum infection. Twenty-four of the 30 cases of Mycobacterium marinum infection presented with multiple lesions or sporotrichoid spread lesions. Ulceration, papules, abscess, and purulent discharge were observed in cases of Mycobacterium abscessus infection. Infective granuloma was most common histopathological appearance. For the treatment of Mycobacterium marinum infection, rifampin, ethambutol, and clarithromycin were commonly used (combination of two antibiotics, or three antibiotics), with the cure rate 90.00%. Four of the six Mycobacterium abscessus infections cases were cured, and one patient died. CONCLUSION: The most common species of sporadic cutaneous infections due to NTM is Mycobacterium marinum. Traumatic injuries, aquarium or fish-related job, and cosmetic surgeries are common risk factors. Mycobacterium marinum infection often presents with nodules, plaques, and sometimes sporotrichoid spread lesions. Lesions of Mycobacterium abscessus infection may vary. Pathological changes were not species specific, final diagnosis must be made depending on the identification of the microorganism. For the treatment of Mycobacterium marinum infection, excellent outcomes can be achieved by the combination of rifampin and ethambutol, and the combination of clarithromycin and rifampin or ethambutoland. Treatment regimens of Mycobacterium abscessus infection should be decided according to the results of antibiotic susceptibility testing.

Effect and mechanism of tacrolimus on melanogenesis on A375 human melanoma cells.

BACKGROUND: Topical tacrolimus has been used for vitiligo as a common treatment option for more than ten years while the underlying mechanism is still uncertain. The aim of this study was to investigate the direct effects of tacrolimus on the melanogenesis and migration on human A375 melanoma cells. The expression of c-KIT mRNA and protein of human A375 cells were also investigated. METHODS: The cultured A375 human melanoma cells were randomly assigned to control and tacrolimus treatment groups (10, 10(2), 10(3) and 10(4) nmol/L). The cell proliferation was measured with Cell Counting Kit-8 assays. Melanin content was measured with NaOH method. Transwell migration assay was used to measure cell migration. The expression of c-KIT mRNA and protein were measured with real-time fluorescence quantitative polymerase chain reaction and immunohistochemistry respectively. RESULTS: The cell proliferation of the 10(3) and 10(4) nmol/L tacrolimus groups were significantly lower (0.666 ± 0.062 and 0.496 ± 0.038) as compared with the control (0.841 ± 0.110, P < 0.05). The mean melanin content in all groups treated with different concentration of tacrolimus (10, 10(2), 10(3), 10(4) nmol/L) increased compared with the control group (P < 0.05). Dose-dependent increase in cell migration were seen in all tacrolimus-treated groups (P < 0.01). The expression of c-KIT mRNA level in A375 cells exposed to tacrolimus (10(3) and 10(4) nmol/L) had significantly increased by 3.03-fold and 3.19-fold respectively compared with the control (P < 0.05). CONCLUSIONS: Although tacrolimus had no effects on cell proliferation on A375 human melanoma cells, it could increase the melanin content and cell migration. The expression of c-KIT mRNA and protein increased dose-dependently in tacrolimus-treated groups as compared with the control. Our study demonstrated that tacrolimus could enhance the melanogenesis and cell migration on A375 cells.

Prevalence of acne vulgaris in Chinese adolescents and adults: a community-based study of 17,345 subjects in six cities.

Acne vulgaris is a common skin condition in adolescents. The prevalence of acne is thought to vary between ethnic groups and countries. A large-scale community-based study was performed in six cities in China to determine the prevalence and possible risk factors for acne in the Chinese population. A total of 17,345 inhabitants were included in this study. Of these, 1,399 were found to have acne. No acne was found in subjects under 10 years of age, and only 1.6% in the 10-year-old group had acne. Prevalence then increased rapidly with age, up to 46.8% in the 19-year-old group. After that, it declined gradually with age. Acne was rare in people over 50 years of age. In subjects in their late teens and 20s, acne was more prevalent in males, while in those over 30 years of age it was more prevalent in females. In subjects with acne, 68.4% had mild; 26.0% had moderate and 5.6% had severe acne. In adult acne, persistent acne was much more common (83.3%) than late-onset acne (16.7%). Smoking and drinking were found to be associated with adolescent acne, while no association was found between diet and acne. These results suggest that the prevalence of acne in the Chinese population is lower than that in Caucasian populations, and that adult acne is not uncommon in Chinese subjects.

Interaction between lanthanum ion and horseradish peroxidase in vitro.

The interaction between lanthanum ion (La(3+)) and horseradish peroxidase (HRP) in vitro was investigated using a combination of biophysical and biochemical methods. When the molar ratio of La(3+) and HRP is low, it was found that the interaction between La(3+) and HRP mainly depends on the electrostatic attraction, van der waals force and hydrogen bond etc. Thus, the interaction is weak and the La-HRP complex cannot be formed in vitro. As expected, the interaction can change the conformation of HRP molecule, leading to the increase in the non-planarity of the porphyrin ring in the heme group of HRP molecule, and then in the exposure degree of the active center, Fe(III) of the porphyrin ring of HRP molecule. Therefore, the catalytic activity of HRP for the H(2)O(2) reduction is improved. When the molar ratio of La(3+) and HRP is high, La(3+) can strongly coordinate with O and/or N in the amide group of the polypeptide chain of HRP molecule, forming the La-HRP complex. The formation of the La-HRP complex causes the change in the conformation of HRP molecule, leading to the decrease in the non-planarity of the porphyrin ring in the heme group of HRP molecule, and then in the exposure degree of the active center, Fe(III) of the porphyrin ring of HRP molecule. Thus, the catalytic activity of HRP for the H(2)O(2) reduction is decreased comparing with that of HRP in the absence of La(3+). The results can provide some references for understanding the interaction mechanism between trace elements ions and peroxidase in living organisms.

Inhibition mechanism of lanthanum ion on the activity of horseradish peroxidase in vitro.

In order to understand the inhibition mechanism of lanthanum ion (La(3+)) on the activity of horseradish peroxidase (HRP), the effects of La(3+) on the activity, electron transfer and conformation of HRP in vitro were investigated by using cyclic voltammetry (CV), atomic force microscopy (AFM), circular dichroism (CD), high performance liquid chromatography (HPLC), matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF/MS) and inductively coupled plasma mass spectrometry (ICP-MS). It was found that La(3+) can combine with the amide groups of the polypeptide chain in HRP molecule, forming the complex of La(3+) and HRP (La-HRP). The formation of the La-HRP complex causes the destruction of the native structure of HRP molecule, leading to the decrease in the non-planarity of the porphyrin ring in the heme group of HRP molecule, and then in the exposure extent of active center, Fe(III) of the porphyrin ring of HRP molecule. Thus, the direct electrochemical and catalytic activities of HRP are decreased. It is a possible inhibition mechanism of La(3+) on the activity of peroxidase.

Inhibition mechanism of Tb(III) on horseradish peroxidase activity.

The inhibition mechanism of Tb(III) on horseradish peroxidase (HRP) in vitro was discussed. The results from MALDI-TOF/MS and X-ray photoelectron spectroscopy (XPS) showed that Tb(III) mainly interacts with the O-containing groups of the amides in the polypeptide chains of the HRP molecules and forms the complex of Tb(III)-HRP, and, in the complex, the molar ratio Tb(III)/HRP is 2 : 1. The results from CD and atomic force microscopy (AFM) indicated that the coordination effect between Tb(III) and HRP can lead to the conformation change in the HRP molecule, in which the contents of alpha-helix and beta-sheet conformation in the peptide of the HRP molecules is decreased, and the content of the random coil conformation is increased. Meanwhile, the coordination effect also leads to the decrease in the content of inter- and intrapeptide-chain H-bonds in the HRP molecules, resulting in the HRP molecular looseness and/or aggregation. Thus, the conformation change in the HRP molecules can significantly decrease the electrochemical reaction of HRP and its electrocatalytic activity for the reduction of H2O2.

The conserved Cys254 plays a crucial role in creatine kinase refolding under non-reduced conditions but not in its activity or stability.

Oxidative stress is a common factor that may affect cell survival in extreme or disease-related conditions, and it is important for the cells to develop not only redox homeostatic mechanisms, but also adequate protein-protecting mechanisms to fight against oxidative stress. In this research, we investigated the role of the conserved C254 in the refolding of creatine kinase (CK), a key cytosolic enzyme involved in intracellular energetics. It was found that the conserved C254 did not contribute to the activity, structure, stability and unfolding of CK, but played a crucial role in CK refolding under non-reduced conditions by preventing off-pathway aggregation. This property of C254 might be a result of natural selection of CK to fight against oxidative stresses that are frequently encountered by vertebrate cells. The results herein not only confirmed that the reduced condition is important to the activity, structural stability and folding of cytosolic proteins, but also highlighted that it is also crucial for cytosolic proteins to maintain the ability to fold correctly under non-reduced conditions.