Single cell landscape of parietal epithelial cells in healthy and diseased states.

The biology and diversity of glomerular parietal epithelial cells (PECs) are important for understanding podocyte regeneration and crescent formation. Although protein markers have revealed the morphological heterogeneity of PECs, the molecular characteristics of PEC subpopulations remain largely unknown. Here, we performed a comprehensive analysis of PECs using single-cell RNA sequencing (scRNA-seq) data. Our analysis identified five distinct PEC subpopulations: PEC-A1, PEC-A2, PEC-A3, PEC-A4 and PEC-B. Among these subpopulations, PEC- A1 and PEC-A2 were characterized as podocyte progenitors while PEC-A4 represented tubular progenitors. Further dynamic signaling network analysis indicated that activation of PEC-A4 and the proliferation of PEC-A3 played pivotal roles in crescent formation. Analyses suggested that upstream signals released by podocytes, immune cells, endothelial cells and mesangial cells serve as pathogenic signals and may be promising intervention targets in crescentic glomerulonephritis. Pharmacological blockade of two such pathogenic signaling targets, proteins Mif and Csf1r, reduced hyperplasia of the PECs and crescent formation in anti-glomerular basement membrane glomerulonephritis murine models. Thus, our study demonstrates that scRNA-seq-based analysis provided valuable insights into the pathology and therapeutic strategies for crescentic glomerulonephritis.

Roles of microRNAs in psoriasis: Immunological functions and potential biomarkers.

MicroRNAs (miRNAs) are small non-coding RNA molecules, which function in RNA silencing and post-transcriptional regulation of gene expression. Psoriasis is an inflammatory skin disease characterized by the dysfunction of keratinocytes, with the immune dysregulation. We reviewed the recent studies on the roles of miRNAs in psoriasis and showed that miRNAs play key roles in psoriasis, including the regulation of hyperproliferation, cytokine and chemokine production in keratinocyte, as well as mediating immune dysfunction in psoriasis. Furthermore, miRNAs, particularly, circulating miRNAs may serve as novel biomarkers for diagnosis, monitoring therapy response and reflecting the disease severity. Thus, targeting specific miRNAs may be used to develop new therapeutic methods for psoriasis.

Formula PSORI-CM01 eliminates psoriasis by inhibiting the expression of keratinocyte cyclin B2.

BACKGROUND: Psoriasis is a chronically recurrent inflammatory skin disease, modern medicine could achieve good therapeutic effect, but these treatments led to recurrence of the psoriasis, more severe symptoms due to damaging skin barrier. Traditional Chinese medicine is a useful alternative therapies. The purpose of this study was to explore the mechanism of PSORI-CM01, a Chinese medicine formula for psoriasis therapy, in eliminating psoriasis by studying its effects on inhibiting epidermal hyperplasia. METHODS: Imiquimod induced psoriasis-form mice model was used to determine the efficacy of PSORICM-01 by assessing the improvement of hyperplasia in epidermal and dermal skin, cyclin B2 expression in skin was detected by immunochemistry. Human keratinocyte cell line HaCaT stimulated by LPS or not was used to research molecular mechanisms of PSORIMCM-01 as in vitro model. The inhibition of proliferation of HaCaT was determined by MTT assay, BrdU assay and real-time cell analysis (RTCA). Cell cycle distribution was detected by flow cytometry. Real-Time PCR and western blot analysis was performed to quantify the mRNA and protein expression levels, respectively. The ability of PSORICM-01 to inhibit proliferation of cyclin B2 overexpressed HaCaT cell were also investigated. RESULTS: PSORI-CM01 significantly inhibited epidermal hyperplasia in IMQ mice lesion skin, and reduced expression of epidermis cyclin B2. Serum containing PSORI-CM01 dramatically inhibited keratinocyte HaCaT cell proliferation, no matter stimulated by LPS or not. FACS analysis showed ability of PSORICM-01 to arrest cell cycle in the G2/M phase. Additionally, PSORI-CM01 significant downregulated mRNA and protein expression of cyclin B2, and over-expression of cyclin B2 antagonized the anti-proliferative effect of PSORI-CM01 on HaCaT cells. CONCLUSIONS: PSORI-CM01 inhibits epidermal hyperplasia in imiquimod-induced mouse psoriasis-form model and reduces keratinocyte proliferation in vitro. Our results indicate that PSORI-CM01 may possess therapeutic potential for psoriasis by inhibiting keratinocyte proliferation through downregulation of cyclin B2.

Two new γ-pyrone glucosides from Paeonia albiflora.

Two new γ-pyrone glucosides, along with three known compounds, were isolated from the roots of Paeonia albiflora, and their structures were elucidated by spectral experiments, chemical analysis, and comparison with literature data. The structures of the new compounds were established as 2-(hydroxymethyl)-4-oxo-4H-pyran-3-yl-6-O-α-L-rhamnopyranosyl-ß-D-glucopyranoside (1), and 2-(hydroxymethyl)-4-oxo-4H-pyran-3-yl-6-O-galloyl-ß-D-glucopyranoside (2). The inhibitory activity on the release of TNF-α of compounds 1-5 was evaluated in vitro. This is the first report of the presence of γ-pyrone glucoside in P. albiflora.

Emerging biomarkers in psoriatic arthritis.

Psoriasis is an immune-mediated skin disease which affects 2-4% of the worldwide population. Approximately 20-30% of patients with psoriasis develop psoriatic arthritis (PsA), a frequently destructive and disabling condition. As skin manifestations precede joint symptoms in nearly all patients with PsA, identification of biomarkers for early prediction of joint damage is an important clinical need. Because not all patients with PsA respond to treatment in the same fashion, identification of biomarkers capable of predicting therapeutic response is also imperative. Here, we review existing literature and discuss current investigations to identify potential biomarkers for PsA disease activity, with particular emphasis on microRNAs as novel markers of interest. Serum (soluble) biomarkers, peripheral osteoclast precursor as cellular biomarkers, and genetic loci associated with skin and joint disease are also reviewed.

Identification and quantitative characterization of PSORI-CM01, a Chinese medicine formula for psoriasis therapy, by liquid chromatography coupled with an LTQ Orbitrap mass spectrometer.

PSORI-CM01 is a Chinese medicine formula prepared from medicinal herbs and used in China for the treatment of psoriasis. However, the chemical constituents in PSORI-CM01 have not been clarified yet. In order to quickly define the chemical profiles and control the quality of PSORI-CM01 preparations, ultra-high liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole Orbitrap mass spectrometry (UHPLC-ESI-LTQ/Orbitrap-MS) was applied for simultaneous identification and quantification of multiple constituents. A total of 108 compounds, including organic acids, phenolic acids, flavonoids, and terpenoids, were identified or tentatively deduced on the base of their retention behaviors, MS and MSn data, or by comparing with reference substances and literature data. In addition, an optimized UHPLC-ESI-MS method was established for the quantitative determination of 14 marker compounds in different dosage forms of PSORI-CM01 preparations. The validation of the method, including spike recoveries, linearity, sensitivity (LOQ), precision, and repeatability, was carried out and demonstrated to be satisfied the requirements of quantitative analysis. This is the first report on the comprehensive determination of chemical constituents in PSORI-CM01 preparations by UHPLC-ESI-LTQ/Orbitrap mass spectrometry. The results suggested that the established methods would be a powerful and reliable analytical tool for the characterization of multi-constituents in complex chemical system and quality control of TCM preparations.

Optimization of astilbin extraction from the rhizome of Smilax glabra, and evaluation of its anti-inflammatory effect and probable underlying mechanism in lipopolysaccharide-induced RAW264.7 macrophages.

Astilbin, a dihydroflavonol derivative found in many food and medicine plants, exhibited multiple pharmacological functions. In the present study, the ethanol extraction of astilbin from the rhizome of smilax glabra Roxb was optimized by response surface methodology (RSM) using Box-Behnken design. Results indicated that the obtained experimental data was well fitted to a second-order polynomial equation by using multiple regression analysis, and the optimal extraction conditions were identified as an extraction time of 40 min, ethanol concentration of 60%, temperature of 73.63 °C, and liquid-solid ratio of 29.89 mL/g for the highest predicted yield of astilbin (15.05 mg/g), which was confirmed through validation experiments. In addition, the anti-inflammatory efficiency of astilbin was evaluated in lipopolysaccharide (LPS)-induced RAW 264.7 cells. Results showed that astilbin, at non-cytotoxicity concentrations, significantly suppressed the production of nitric oxide (NO) and tumor necrosis factor-α (TNF-α), as well as the mRNA expression of inducible nitric oxide synthase (iNOS) and TNF-α in LPS-induced RAW 264.7 cells, but did not affect interleukin-6 (IL-6) release or its mRNA expression. These effects may be related to its up-regulation of the phosphorylation of p65, extracellular signal-regulated kinases 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK).

Qualitative and quantitative analysis of Rhizoma Smilacis glabrae by ultra high performance liquid chromatography coupled with LTQ OrbitrapXL hybrid mass spectrometry.

Rhizoma Smilacis glabrae, a traditional Chinese medicine (TCM) as well as a functional food, has been commonly used for detoxification treatments, relieving dampness and as a diuretic. In order to quickly define the chemical profiles and control the quality of Smilacis glabrae, ultra high performance liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole orbitrap mass spectrometry (UHPLC-ESI/LTQ-Orbitrap-MS) was applied for simultaneous identification and quantification of its bioactive constituents. A total of 56 compounds, including six new compounds, were identified or tentatively deduced on the basis of their retention behaviors, mass spectra, or by comparison with reference substances and literature data. The identified compounds belonged to flavonoids, phenolic acids and phenylpropanoid glycosides. In addition, an optimized UHPLC-ESI/LTQ-Orbitrap-MS method was established for quantitative determination of six marker compounds from five batches. The validation of the method, including linearity, sensitivity (LOQ), precision, repeatability and spike recoveries, was carried out and demonstrated to be satisfied the requirements of quantitative analysis. The results suggested that the established method would be a powerful and reliable analytical tool for the characterization of multi-constituent in complex chemical system and quality control of TCM.

[Pharmacokinetic study on peoniflorin, astilbin, rosmarinic acid, isofraxidin and liquiritin in rat blood after oral administration of shaolin xiaoyin tablets].

To establish a method for the determination of astilbin, peoniflorin, rasmarinci acid, isofraxidin and liquiritin contained in Shaolin Xiaoyin tablets, in order to lay a foundation for designing late-stage dosage forms and clinical medication schemes. In this paper, efforts were made to establish a method for the determination of the blood concentration of the five components and study the in vivo pharmacokinetics in rats. The blood concentration was determined by HPLC. Phenomenex C18 column (4.6 mm x 250 mm, 5 microm) was adopted and eluted with methanol-acetonitrile-0.05% formic acid, the flow rate was 0.8 mL x min(-1), and the wavelength was 275 nm. The samples were processed by the solid phase extraction method. After oral administration of Shaoling Xiaoyin tablets, the rat bloods were collected at different time points to determine the blood concentrations. The experimental results showed that the baseline separation could be adopted for the five components, and astilbin, peoniflorin, rasmarinci acid, isofraxidin and liquiritin showed good linear relations within ranges of 2.48-248, 0.213 6-21.36, 0.531-53.1, 0.704-70.4, 0.253-25.3 mg x L(-1). All the five components could be absorbed in blood and excreted quickly. The method established in this paper is rapid and accurate, and could be used for in vivo analysis on preparations containing similar components. The main components in Shaoling Xiaoyin tablets could be absorbed and excreted quickly, and thus suitable to be made into sustained release tablets. Common preparations are required to be taken for 4-6 times a day.

Anti HSV-1 flavonoid derivatives tethered with houttuynin from Houttuynia cordata.

This paper reports the phytochemical investigation of the 50% aq. EtOH extract of Houttuynia cordata, an effective TCM and functional food in China, which led to the isolation of 17 flavonoids including four new ones. The four new compounds were flavonoid derivatives tethered with houttuynin (3-oxododecanal). Each of the new compounds was obtained as a pair of inseparable diasteriomeric epimers due to the chiral carbon of hemiketal at C-3″. This phenomenon is rooted in the ring-chain tautomerism of the hemiketal functional group in solution, which was proved by dynamic NMR experiments. The new compounds 1-4 displayed inhibitory activities against herpes simplex virus 1, with respective IC50 values of 38.46, 14.10, 62.00 and 70.76 µM, which was associated with the medicinal functions of H. cordata.

Melanocortin-4 receptor expression in the rostral ventromedial medulla involved in modulation of nociception in transgenic mice.

The rostral ventromedial medulla (RVM) is a prominent component of the descending modulatory system involved in the control of spinal nociceptive transmission. In the current study, we investigated melanocortin-4 receptor (MC4R) expression in the RVM, where the neurons involved in modulation of nociception reside. Using a line of mice expressing green fluorescent protein (GFP) under the control of the MC4R promoter, we found a large number of GFP-positive neurons in the RVM [nucleus raphe magnus (NRM) and nucleus gigantocellularis pars α (NGCα)]. Fluorescence immunohistochemistry revealed that approximately 10% of MC4R-GFP-positive neurons coexpressed tyrosine hydroxylase, indicating that they were catecholaminergic, whereas 50%-75% of those coexpressed tryptophan hydroxylase, indicating that they were serotonergic. Our findings support the hypothesis that MC4R signaling in RVM may modulate the activity of serotonergic sympathetic outflow sensitive to nociceptive signals, and that MC4R signaling in RVM may contribute to the descending modulation of nociceptive transmission.

Determination of isofraxidin and astilbin by HPLC in rat plasma and its application after orally administration the extract of Sarcandra glabra.

Sarcandra glaber is a common traditional Chinese medicine used to treat psoriasis and other infectious diseases, isofraxidin and astilbin are the main components of it. In order to study the pharmacokinetics of Sarcandra glabra, an HPLC method for simultaneous determination of isofraxidin and astilbin in rat plasma was established. Plasma samples were prepared using solid phase extraction method. C(18) column with a guard was used, mobile phase was consisted of A (methanol) and B (0.1% aqueous acetic acid) with gradient elution as follows: 0 - 4min, A: 35%, B: 65%; 4 - 10min, A: 35% - 45%, B: 65% - 55%; 10 - 20min, A: 45%, B: 55%. The flow rate was 1.2 mL/min from 0 to 4 min, 1.0 mL/min from 4 to 20 min. The detection wavelength was 300 nm. A linear correlation between drug amount and peak area was established for isofraxidin in the range of 20-320 ng and for astilbin in the range of 19-304 ng. The recovery was over 68% for both compounds, the accuracy was within 8%, and the inter-day and intra-day precisions were all less than 8%. The pharmacokinetics of isofraxidin and astilbin was studied after orally administration the extract of Sarcandra glabra.

Corrigendum: Deep sequencing of plasma exosomal microRNA level in psoriasis vulgaris patients.

[This corrects the article DOI: 10.3389/fmed.2022.895564.].

Metabolic rewiring in keratinocytes by miR-31-5p identifies therapeutic intervention for psoriasis.

Besides genetic alterations, the cellular environment also determines disease onset and progression. When different cell types contribute to disease outcome, this imposes environmental challenges as different cell types likely differ in their extracellular dependencies. Hsa-microRNA-31-5p (miR-31) is highly expressed in keratinocytes of psoriatic skin, and we show that expression in keratinocytes is induced by limited glucose availability and enables increased survival under limiting glucose conditions by increasing glutamine metabolism. In addition, miR-31 expression results in not only secretion of specific metabolites (aspartate and glutamate) but also secretion of immunomodulatory factors. We show that this miR-31-induced secretory phenotype is sufficient to induce Th17 cell differentiation, a hallmark of psoriasis. Inhibitors of miR31-induced metabolic rewiring and metabolic crosstalk with immune cells alleviate psoriasis pathology in a mouse model of psoriasis. Together our data illustrate an emerging concept of metabolic interaction across cell compartments that characterizes disease development, which can be employed to design effective treatment options for disease, as shown here for psoriasis.

[Analysis of saponins in Panax notoginseng by UPLC-LTQ-Orbitrap MS/MS].

A method for qualitative analysis of constituents in Panax notoginseng by UPLC-LTQ-Orbitrap mass spectrometry was established. Based on the high-resolution mass information, MS/MS fragmentation behaviors and chemical components from literatures, 43 compounds were identified or tentatively characterized. New type saponin aglycone, combined with malonyl-substituted and acetyl-substituted saponins were discovered and plausibly identified in this study. This work could be helpful for the quality control and further phytochemical studies of Panax notoginseng, and provided a good example for the analysis of chemical constituents in traditional Chinese medicine.

[Study on the correlation between Chinese medicine syndrome types in influenza A (H1N1) virus and potential biomarkers].

OBJECTIVE: To investigate the contents changes of potential biomarkers of patients infected with influenza A (H1N1) virus of different Chinese medicine (CM) syndrome types. METHODS: Eighty-two patients with influenza A (H1N1) virus were differentiated as three syndrome types, i. e., wind-heat invading weifen syndrome (51 cases), heat-toxicity attacking Fei syndrome (22 cases), and superficies tightened by wind cold syndrome (9 cases) according to Chinese medicine syndrome typing. According to patients' willingness and clinical conditions, they were treated by three therapeutic schedules, i. e., herbal therapy, symptomatic treatment, and antiviral therapy. The changes of potential biomarkers contents were detected in the serum of patients of various syndrome types before and after treatment. Results There was no statistical difference in the potential biomarkers contents correlated to symptoms of fever, inflammation and cough, such as PGG2, 20-COOH-LTB4, homocystein, and so on in the serum of patients of various syndrome types before treatment (P > 0.05). There was statistical difference in the potential biomarkers such as 20-OH-LTE4, LTA4, and linolenic acid, etc. between superficies tightened by wind cold syndrome and wind-heat invading weifen syndrome (P < 0.05, P < 0.01). There was statistical difference in the potential biomarkers such as PGF1alpha, prostanoic acid, and etc. between superficies tightened by wind cold syndrome and heat-toxicity attacking Fei syndrome (P < 0.05, P < 0.01). Statistical difference existed in other indices other than dUTP; 5,10-methylene-THF and PGF1alpha in wind-heat invading weifen syndrome and superficies tightened by wind cold syndrome; prostanoic acid, homocysteine, and glucose in superficies tightened by wind cold syndrome when compared with before treatment in the same group (P < 0.05, P < 0.01). The changing tendency of potential biomarkers among different syndrome types was identical. Of them, the change of 6-keto-PGF1alpha content was the most obviously of all indices. CONCLUSION: There was difference in the contents of potential biomarkers of patients infected with influenza A (H1N1) virus of different syndrome types, and our study provided experimental data support for the objectiveness of CM syndrome differentiation from the perspective of metabolic substances.

[Adverse events/adverse reactions of acupoint catgut embedding therapy for psoriasis vulgaris: a systematic review].

OBJECTIVE: To systematically review the occurrence of adverse events/adverse reactions (AEs/ARs) induced by acupoint catgut embedding therapy for psoriasis vulgaris (PV) and its safety. METHODS: Randomized controlled trials, controlled clinical trials, cohort studies, case-control studies, case-series, and case reports concerning the treatment of PV with acupoint catgut embedding therapy were searched from Chinese and English databases from their inception to January 7th, 2021. The AEs/ARs related to acupoint catgut embedding therapy for PV were subjected to descriptive statistics, followed by the analysis of possible reasons. RESULTS: Finally, 16 studies were included, involving 1 158 patients. A total of 79 cases were reported to present with mild to moderate AEs/ARs related to acupoint catgut embedding therapy for PV, and there were no serious AEs/ARs or death cases. The most common AEs/ARs were local redness, swelling, heat, and pain (31.65%,25/79), followed by low-grade fever and fatigue (29.11%,23/79), isomorphic reaction (16.46%,13/79), local induration (13.92%,11/79), and fainting (8.86%,7/79). In terms of embedding materials, catgut (93.67%,74/79) and lumbar puncture needles or other puncture needles (49.37%,39/79) were proved the most common AEs/ARs-inducing factors. The proportion of AEs/ARs resulting from treatment interval≤two weeks (67.09%,53/79) and treatment course≤eight weeks (55.70%,44/79) was relatively high. Because the incidence of AEs/ARs fails to be calcula-ted, it is not yet possible to accurately assess the risk and safety of acupoint catgut embedding therapy for PV. CONCLUSION: Available evidence suggests that in the treatment of PV, acupoint catgut embedding therapy may induce a series of mild to moderate AEs/ARs, so its clinical practice deserves attention. We should strictly grasp its indications and contraindications, and prevent the occurrence of related AEs/ARs by standardizing the operation and improving the embedding materials.

Deep Sequencing of Plasma Exosomal microRNA Level in Psoriasis Vulgaris Patients.

Psoriasis is a chronic skin disease affecting 1% to 3% of the world population. Psoriasis vulgaris (PV) is the most common form of psoriasis. PV patients suffer from inflamed, pruritic and painful lesions for years (even a lifetime). However, conventional drugs for PV are costly. Considering the need for long-term treatment of PV, it is urgent to discover novel biomarkers and therapeutic targets. Plasma exosomal miRNAs have been identified as the reliable biomarkers and therapy targets of human diseases. Here, we described the levels of serum exosomal miRNAs in PV patients and analyzed the functional features of differently expressed miRNAs and their potential target genes for the first time. We identified 1182 miRNAs including 336 novel miRNAs and 246 differently expressed miRNAs in serum exosomes of healthy people and PV patients. Furthermore, the functional analysis found differently expressed miRNA-regulated target genes enriched for specific GO terms including primary metabolic process, cellular metabolic process, metabolic process, organic substance metabolic process, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway containing cellular processes, human diseases, metabolic pathways, metabolism and organismal systems. In addition, we found that some predicted target genes of differentially expressed miRNAs, such as CREB1, RUNX2, EGFR, are both involved in inflammatory response and metabolism. In summary, our study identifies many candidate miRNAs involved in PV, which could provide potential biomarkers for diagnosis of PV and targets for clinical therapies against PV.

[Correlation between T lymphocyte subsets and different syndrome types in patients with influenza A (H1N1): a retrospective study].

OBJECTIVE: To investigate the changes in T lymphocyte subsets in patients with different syndrome types infected by influenza A (H1N1) virus after treatment. METHODS: In this retrospective study, 111 patients with H1N1 influenza were enrolled and divided into three groups according to their syndromes: exterior heat syndrome group (55 cases), exterior cold syndrome group (20 cases) and heat toxin invading lung (HTIL) syndrome group (36 cases). Patients were treated with Western medicine (acetaminophen or ibuprofen suspension), traditional Chinese medicine (herbal medicine according to their syndromes), or a combination of Western medicine and traditional Chinese medicine with patient's intentions. Another 20 healthy people were selected as normal control. Phenotypic features of T lymphocyte subsets in peripheral vein blood of patients before and after treatment were determined by flow cytometry. RESULTS: Before treatment, the numbers of CD3- and CD4-positive T lymphocytes were lower in H1N1 patients with the three types of syndromes than in the normal controls (P<0.01), and the numbers of CD8-positive T lymphocytes were lower in exterior heat syndrome and HTIL syndrome groups than in normal control group (P<0.01). The ratio of CD4-positive to CD8-positive T lymphocytes in exterior cold syndrome group showed no difference as compared with the normal control group, and the ratios of CD4-positive to CD8-positive T lymphocytes in exterior heat syndrome and HTIL syndrome groups were higher than that in the normal control group (P<0.01). After treatment, the numbers of CD4-positive T lymphocytes increased in all the three types of syndromes in patients with H1N1, and showed no difference compared with the normal control group. The numbers of CD3-positive T lymphocytes in patients with exterior heat syndrome and exterior cold syndrome increased, and showed no difference compared with the normal control group. The number of CD3-positive T lymphocytes in H1N1 patients with HTIL syndrome was lower than that in the normal control group (P<0.05), whereas the numbers of CD8-positive T lymphocytes in patients with exterior heat syndrome and HTIL syndrome were lower than that in the normal control group (P<0.05). The ratio of CD4-positive to CD8-positive T lymphocytes in patients with HTIL syndrome was decreased, and displayed no difference as compared with the normal control group. The ratio of CD4-positive to CD8-positive T lymphocytes in patients with exterior heat syndrome was higher than that in the normal control group (P<0.05). CONCLUSION: Analysis of T lymphocyte subsets may provide experimental data to support for syndrome differentiation in traditional Chinese medicine and a sound method to establish syndrome differentiation typing for H1N1.

Total Glucosides of Paeony Ameliorate Pristane-Induced Lupus Nephritis by Inducing PD-1 ligands+ Macrophages via Activating IL-4/STAT6/PD-L2 Signaling.

Macrophages, a major subset of innate immune cells, are main infiltrating cells in the kidney in lupus nephritis. Macrophages with different phenotypes exert diverse or even opposite effects on the development of lupus nephritis. Substantial evidence has shown that macrophage M2 polarization is beneficial to individuals with chronic kidney disease. Further, it has been reported that PD-1 ligands (PD-Ls) contribute to M2 polarization of macrophages and their immunosuppressive effects. Total glucosides of paeony (TGP), originally extracted from Radix Paeoniae Alba, has been approved in China to treat some autoimmune diseases. Here, we investigated the potentially therapeutic effects of TGP on lupus nephritis in a pristane-induced murine model and explored the molecular mechanisms regulating macrophage phenotypes. We found that TGP treatment significantly improved renal function by decreasing the urinary protein and serum creatinine, reducing serum anti-ds-DNA level and ameliorating renal immunopathology. TGP increased the frequency of splenic and peritoneal F4/80+CD11b+CD206+ M2-like macrophages with no any significant effect on F4/80+CD11b+CD86+ M1-like macrophages. Immunofluorescence double-stainings of the renal tissue showed that TGP treatment increased the frequency of F4/80+Arg1+ subset while decreasing the percentage of F4/80+iNOS+ subset. Importantly, TGP treatment increased the percentage of both F4/80+CD11b+PD-L1+ and F4/80+CD11b+PD-L2+ subsets in spleen and peritoneal lavage fluid as well as the kidney. Furthermore, TGP augmented the expressions of CD206, PD-L2 and phosphorylated STAT6 in IL-4-treated Raw264.7 macrophages in vitro while its effects on PD-L2 were abolished by pretreatment of the cells with an inhibitor of STAT6, AS1517499. However, TGP treatment did not affect the expressions of STAT1 and PD-L1 in Raw264.7 macrophages treated with LPS/IFN-γ in vitro, indicating a possibly indirect effect of TGP on PD-L1 expression on macrophages in vivo. Thus, for the first time, we demonstrated that TGP may be a potent drug to treat lupus nephritis by inducing F4/80+CD11b+CD206+ and F4/80+CD11b+PD-L2+ macrophages through IL-4/STAT6/PD-L2 signaling pathway.