Inhibin βE subunit (INHBE) is a member of the transforming growth factor-β (TGF-β) superfamily, highly specifically expressed in liver cells. The precursor protein of INHBE generates the inhibin β subunit after proteolytic processing. This protein is associated with various cellular processes, including cell proliferation, apoptosis, immune response, and hormone secretion. During the development of obesity and diabetes, the expression of INHBE protein inhibits the proliferation and growth of relevant cells in the pancreas and liver. Research has found a positive correlation between INHBE expression in the liver and insulin resistance and body mass index (BMI), suggesting that INHBE may be a liver factor in altering systemic metabolic status under conditions of obesity-related insulin resistance ^[1]. The studies conducted by Alnylam Pharmaceuticals and the Regeneron Genetics Center (RGC), respectively, revealed the close relationship between INHBE and fat regulation. The research demonstrated that rare loss-of-function variants in INHBE may protect the liver from the impact of inflammation, abnormal blood lipids, and type 2 diabetes by promoting healthy fat storage. Patients carrying such mutations exhibit more normal fat distribution, significantly reduced abdominal fat, improved metabolic conditions, and a decreased risk of cardiovascular diseases and type 2 diabetes ^[2-4]. These findings suggest that INHBE is a liver-specific negative regulator of fat storage. Inhibiting the expression of INHBE genes and proteins may be a potential strategy for treating metabolic disorders related to improper fat distribution and storage. Consequently, several small nucleic acid pharmaceutical companies, including Alnylam Pharmaceuticals, Arrowhead Pharmaceuticals, and Wave Life Sciences, are currently developing RNA interference (RNAi) drugs targeting INHBE to treat conditions such as obesity ^[5-7]. RNAi drugs primarily include small interfering RNA (siRNA) and antisense oligonucleotides (ASO). siRNA targets and degrades specific mRNA, while ASO binds to the target mRNA, preventing its translation or inducing its degradation, thereby inhibiting the expression of the target gene. Considering the genetic differences between humans and animals, humanizing mouse genes can accelerate the clinical development of RNAi therapies targeting human INHBE. This strain is a mouse Inhbe gene humanized model and can be used to study therapies targeting INHBE for obesity. The homozygous B6-huINHBE mice are viable and fertile. In addition, based on the independently developed TurboKnockout fusion BAC recombination technology, Cyagen can also generate hot mutation models based on this strain and provide customized services for specific mutations to meet the experimental needs in pharmacology and other fields.

The SLC16A1 gene encodes the Monocarboxylate Transporter 1 (MCT1) protein, a vital proton-coupled symporter that facilitates the rapid transmembrane movement of metabolic substrates, including lactate, pyruvate, and ketone bodies (acetoacetate and β-hydroxybutyrate). This gene is ubiquitously expressed across nearly all human tissues to maintain energy balance and pH homeostasis, with notably high levels labeled in the heart, oxidative skeletal muscle fibers, erythrocytes (red blood cells), and the brain (specifically in oligodendrocytes and the blood-brain barrier), while being uniquely "disallowed" or suppressed in normal pancreatic beta-cells to prevent inappropriate insulin release ^[1]. Functionally, MCT1 is central to the "lactate shuttle" mechanism, allowing tissues to coordinate metabolic fuel exchange by facilitating either the influx or efflux of substrates depending on the concentration gradient and proton motive force ^[2]. Mutations in SLC16A1 are clinically linked to Erythrocyte Lactate Transporter Defect, which causes exercise-induced muscle cramping and fatigue, and Monocarboxylate Transporter 1 Deficiency, a rare disorder characterized by recurrent episodes of severe ketoacidosis and vomiting triggered by fasting or infection ^[3]. Conversely, gain-of-function mutations in the gene's promoter lead to familial hyperinsulinemia type 7 (HHF7), where exercise triggers excessive insulin secretion, while its widespread overexpression in various cancers (such as melanoma and lung cancer) supports the Warburg effect by managing lactate efflux to prevent intracellular acidification and fueling tumor progression ^[4]. The B6-huSLC16A1 mouse is a humanized model constructed through gene-editing technology, in which the sequences from the ATG start codon to the TGA stop codon of the endogenous mouse Slc16a1 gene are replaced with the sequences from the ATG start codon to the TGA stop codon of the human SLC16A1 gene. This model can be used for research on diseases such as Erythrocyte Lactate Transporter Defect, Monocarboxylate Transporter 1 Deficiency, familial hyperinsulinemia type 7 (HHF7), and various cancers, as well as for screening, development, and preclinical evaluation of SLC16A1-targeted therapeutics.

B6-Uox KO/huURAT1 mice are humanized disease models obtained by crossing Uox KO mice (catalog No.: C001232) with B6-huURAT1 mice (catalog No.: C001704). This model can be used for studying the pathological mechanisms and treatment methods of uric acid metabolism-related diseases such as hyperuricemia and gout, as well as for screening and developing URAT1-targeted therapies and evaluating preclinical efficacy and safety. It is worth noting that heterozygous Uox KO mice can survive and are fertile, while homozygous Uox KO mice need to be maintained with drugs such as Allopurinol after birth.

The B6-Uox KO/huXDH mice are humanized disease models obtained by mating Uox KO mice (catalog No.: C001232) with B6-huXDH mice (catalog No.: C001586). This model is suitable for studying the pathological mechanisms of hyperuricemia and gout, and provides an ideal preclinical research platform for the development of novel xanthine oxidase inhibitors and small nucleic acid therapies. It is worth noting that heterozygous Uox KO mice can survive and are fertile, while homozygous Uox KO mice require drugs such as Allopurinol to maintain their survival after birth.

The B6-hGIPR/huGCGR/hGLP-1R mouse is a triple-gene humanized model obtained by mating B6-hGIPR/hGLP-1R mice (catalog No.: C001599) with B6-huGCGR mice (catalog No.: C001723). This model can be used for studying the pathogenic mechanisms and developing treatment methods for glucose-related metabolic diseases such as obesity, type 2 diabetes (T2D), and steatohepatitis, as well as for the development of GIPR/GLP-1R/GCGR-targeted drugs.

The B6-hAGT/hREN/huPCSK9 mouse is a humanized model obtained by mating the hREN x hAGT mouse (catalog No.: C001336) with the B6-huPCSK9 mouse (catalog No.: C001617). This model can be used for mechanism research on chronic hypertension, various metabolic diseases, neurodegenerative diseases, and tumorigenesis, as well as the development of relevant treatment methods.

Proprotein convertase subtilisin/kexin 9 (PCSK9) is a serine protease primarily produced in the liver but expressed in other tissues, including the intestine, heart, and neurons. The N-terminal domain of the PCSK9 protein is responsible for protein localization and stability, while the C-terminal domain is responsible for protein enzymatic activity ^[1]. The Low-density lipoprotein receptor (LDLR) is a receptor that is responsible for clearing low-density lipoprotein cholesterol (LDL-C) from the blood. PCSK9 cleaves the intracellular domain of LDLR on the cell surface, causing it to detach from the cell membrane and be transported to the lysosome for degradation, promoting LDLR degradation, and increasing plasma LDL-C. Overexpression or gain-of-function mutations of the PCSK9 gene can lead to LDL-C accumulation by reducing LDLR levels. This can cause hypercholesterolemia, which increases the risk of cardiovascular diseases, such as atherosclerosis and coronary heart disease, and neurodegenerative diseases, such as Alzheimer's disease ^[2]. PCSK9 has become an important target for the development of lipid-lowering drugs. Several PCSK9-targeted antibodies or small nucleic acid drugs have been approved for marketing worldwide, including evolocumab from Amgen, alirocumab from Sanofi and Regeneron, and inclisiran from Novartis. These drugs primarily work by inhibiting PCSK9 activity or preventing PCSK9 protein from binding to LDLR, lowering LDL-C levels in the blood to treat hypercholesterolemia ^[3-4]. In addition, PCSK9 can promote tumor growth and development by regulating cell proliferation, migration, and invasion. It can also regulate the expression of inflammatory factors that contribute to inflammation. Therefore, targeting the expression of PCSK9 has been investigated in tumor immunotherapy and autoimmune disease therapy ^[5-6]. B6-hPCSK9 mice are a humanized model generated by gene editing technology to replace the mouse Pcsk9 gene with the human PCSK9 gene sequence. These mice express human PCSK9 protein and can be used for research on various metabolic diseases, neurodegenerative diseases, tumor development, autoimmune disease mechanisms, and for the preclinical pharmacological evaluation of PCSK9-targeted drugs. In addition, Cyagen has developed a similar model, the B6-hPCSK9(CDS) mouse (PCSK9 coding sequence humanized model, Catalog Number: C001593). Compared to the B6-hPCSK9 mouse model, the B6-hPCSK9(CDS) mouse expresses higher levels of human PCSK9 and exhibits LDLR protein expression closer to physiological levels. It is recommended to choose the appropriate model based on the type of drug or research direction.

The B6-huGCGR/hGLP1R mouse is a dual-gene humanized model obtained by mating B6-huGCGR mice (catalog No.: C001723) with B6-hGLP-1R mice (catalog No.: C001421). This model can be used for studying the pathogenesis of glucose-related metabolic diseases such as obesity, type 2 diabetes (T2D), and steatohepatitis, as well as for the screening, development, and safety evaluation of drugs targeting GCGR/GLP1R.

The B6-huGDF8/huTFRC mouse is a dual-gene humanized model obtained by mating B6-huMSTN (huGDF8) mice (catalog No.: C001636) with B6-huTFRC mice (catalog No.: C001860). Transferrin receptor 1 (TFR1 or TFRC) is highly expressed in brain endothelial cells and muscle cells. It can be used as a target for receptor-mediated transcytosis (RMT) to achieve efficient transport of macromolecular drugs across the blood-brain barrier (BBB) and into muscle tissues. This model can be used for research on the pathological mechanisms and treatment methods of muscular atrophy, sarcopenia, metabolic syndrome, and iron metabolism diseases, as well as for the development of MSTN/TFRC targeted drugs.

Complement factor B (CFB) is a circulating serine protease that plays a central role in the alternative pathway of the complement system, a critical component of innate immunity. Encoded by the CFB gene, this protein is primarily synthesized by hepatocytes, adipocytes, and monocytes, reflecting its systemic and local involvement in immune surveillance and inflammation ^[1]. Upon activation by factor D, CFB forms the active enzyme factor Bb, which, in complex with complement component C3b, constitutes the alternative pathway C3 convertase (C3bBb). This convertase catalyzes the cleavage of C3 into the anaphylatoxin C3a and the opsonin C3b, leading to the amplification of the complement cascade and the subsequent elimination of pathogens and damaged cells ^[2]. Dysregulation of CFB activity, often stemming from genetic polymorphisms within the CFB locus, has been implicated in the pathogenesis of several human diseases, including age-related macular degeneration (AMD), atypical hemolytic uremic syndrome (aHUS), and systemic lupus erythematosus (SLE), underscoring the delicate balance required for proper complement regulation and immune homeostasis ^[3-4]. These associations highlight CFB as a key mediator of both protective and pathological immune responses. The MASP2 gene encodes MASP-2, a serum serine protease that serves as a key mediator in complement system activation. MASP-2 initiates the lectin pathway by forming complexes with pattern recognition molecules such as mannose-binding lectin (MBL) and ficolins. Upon pathogen recognition by MBL, MASP-2 is activated and subsequently cleaves complement components C4 and C2, leading to the generation of C3 convertase and triggering downstream complement activation. Beyond its role in the complement cascade, MASP-2 also contributes to the coagulation pathway by cleaving prothrombin to generate thrombin, thereby linking innate immunity and hemostasis ^[5]. Emerging evidence highlights the clinical significance of MASP2 gene polymorphisms, which are associated with altered susceptibility to infectious diseases and immune-related disorders. Reduced plasma levels of MASP-2 have been linked to increased vulnerability to HIV infection, while elevated MASP-2 activity may exacerbate inflammatory responses ^[6]. Given its pivotal role in immune regulation, MASP-2 has emerged as a promising therapeutic target. Inhibition of MASP-2 is currently under investigation as a potential strategy for treating a range of conditions, including IgA nephropathy (IgAN) ^[7], atypical hemolytic uremic syndrome (aHUS), and transplant-associated thrombotic microangiopathy (TA-TMA) ^[8]. The B6-huCFB/hMASP2 mouse is a dual-gene humanized model obtained by mating B6-huCFB mice (catalog number: C001710) with B6-hMASP2 mice (catalog number: C001592). This model can be used for research on the pathological mechanisms and treatment methods of autoimmune diseases and infectious diseases, as well as the development of CFB/MASP2-targeted drugs.