B cell metabolism in autoimmune diseases: signaling pathways and interventions

Autoimmune diseases are heterogeneous disorders believed to stem from the immune system’s inability to distinguish between auto- and foreign- antigens. B lymphocytes serve a crucial role in humoral immunity as they generate antibodies and present antigens. Dysregulation of B cell function induce the onset of autoimmune disorders by generating autoantibodies and pro-inflammatory cytokines, resulting in an imbalance in immune regulation. New research in immunometabolism shows that cellular metabolism plays an essential role in controlling B lymphocytes immune reactions by providing the energy and substrates for B lymphocytes activation, differentiation, and function. However, dysregulated immunometabolism lead to autoimmune diseases by disrupting self-tolerance mechanisms. This review summarizes the latest research on metabolic reprogramming of B lymphocytes in autoimmune diseases, identifying crucial pathways and regulatory factors. Moreover, we consider the potential of metabolic interventions as a promising therapeutic strategy. Understanding the metabolic mechanisms of B cells brings us closer to developing novel therapies for autoimmune disorders

Establishment and optimization of an in vitro guinea pig oocyte maturation system.

Guinea pigs are a valuable animal model for studying various diseases, including reproductive diseases. However, techniques for generating embryos via embryo engineering in guinea pigs are limited; for instance, in vitro maturation (IVM) technique is preliminary for guinea pig oocytes. In this study, we aimed to establish and optimize an IVM method for guinea pig oocytes by investigating various factors, such as superovulation induced by different hormones, culture supplementation (e.g., amino acids, hormone, and inhibitors), culture conditions (e.g., oocyte type, culture medium type, and treatment time), and in vivo hCG stimulation. We found that oocytes collected from guinea pigs with superovulation induced by hMG have a higher IVM rate compared to those collected from natural cycling individuals. Moreover, we found that addition of L-cysteine, cystine, and ROS in the culture medium can increase the IVM rate. In addition, we demonstrated that in vivo stimulation with hCG for 3-8 h can further increase the IVM rate. As a result, the overall IVM rate of guinea pig oocytes under our optimized conditions can reach ~69%, and the mature oocytes have high GSH levels and normal morphology. In summary, we established an effective IVM method for guinea pig oocytes by optimizing various factors and conditions, which provides a basis for embryo engineering using guinea pigs as a model

S1 Dataset -

Guinea pigs are a valuable animal model for studying various diseases, including reproductive diseases. However, techniques for generating embryos via embryo engineering in guinea pigs are limited; for instance, in vitro maturation (IVM) technique is preliminary for guinea pig oocytes. In this study, we aimed to establish and optimize an IVM method for guinea pig oocytes by investigating various factors, such as superovulation induced by different hormones, culture supplementation (e.g., amino acids, hormone, and inhibitors), culture conditions (e.g., oocyte type, culture medium type, and treatment time), and in vivo hCG stimulation. We found that oocytes collected from guinea pigs with superovulation induced by hMG have a higher IVM rate compared to those collected from natural cycling individuals. Moreover, we found that addition of L-cysteine, cystine, and ROS in the culture medium can increase the IVM rate. In addition, we demonstrated that in vivo stimulation with hCG for 3–8 h can further increase the IVM rate. As a result, the overall IVM rate of guinea pig oocytes under our optimized conditions can reach ~69%, and the mature oocytes have high GSH levels and normal morphology. In summary, we established an effective IVM method for guinea pig oocytes by optimizing various factors and conditions, which provides a basis for embryo engineering using guinea pigs as a model.</div

Types of oocytes from guinea pigs and their meiotic progression during IVM.

The arrow indicates the first polar body of the matured oocytes, indicating the oocytes have entered the MII phase. (A) Matured oocytes stained with Cell Truck Bule CMF2HC under the microscope after treatment with ROS for 12 hours. (B) Immature oocytes stained with Cell Truck Bule CMF2HC under the microscope after treatment with ROS for 12 hours. (C) After the removal of IMBX, the fluorescence intensity of matured oocytes treated with IBMX was significantly stronger than that treated with ROS. (D) The fluorescence intensity of GSH in MII oocytes cultured in the maturation medium was relatively weaker, and the first polar body was not obvious as well, compared with that cultured in the maturation medium with ROS. (E) The fluorescence intensity of GSH in MII oocytes cultured in MTA medium supplemented with L-cysteine and cystine was stronger than that of GSH in MII oocytes cultured in basic medium. (F) The fluorescence intensity of GSH cultured in the basic medium was much lower than other groups.</p

Effects of different hormones on superovulation and on the IVM rate of oocytes from these superovulated guinea pigs.

Effects of different hormones on superovulation and on the IVM rate of oocytes from these superovulated guinea pigs.</p

Effects of different doses of hCG on the IVM rate of oocytes from superovulated guinea pigs.

Effects of different doses of hCG on the IVM rate of oocytes from superovulated guinea pigs.</p

The microtubule morphology of MII oocytes from guinea pigs was divided into two types.

For MII oocytes with normal spindles and aggregated chromosomes (A, B and C in the top panel), the chromosomes were distributed and aggregated on the equatorial plate, while for MII oocytes with abnormal spindles and dispersed chromosomes (D, E and F in the bottom panel), the chromosomes could not be neatly distributed on the equatorial plate and are in a diffusion state. A and D are for Hoechst 33342 staining, B and E are for β-tubulin staining, and C and F are merged for A and B, and D and E, respectively. Bar in 50 μm.</p

Effects of different amino acids and inhibitors on the IVM rate of guinea pig oocytes.

Effects of different amino acids and inhibitors on the IVM rate of guinea pig oocytes.</p

Effects of different culture media on intracellular levels of GSH and morphology of microtubules in MII oocytes.

Effects of different culture media on intracellular levels of GSH and morphology of microtubules in MII oocytes.</p