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Oncostatin M (OSM) is a pleiotropic cytokine belonging to the Interleukin-6 (IL-6) family; it participates in various inflammatory processes, such as wound healing, liver regeneration, and bone remodeling. In addition to OSM, members of the IL-6 family include IL-6, Leukemia Inhibitory Factor (LIF), IL-11, IL-27, IL-31, Cardiotrophin-1 (CT-1), Ciliary Neurotrophic Factor (CNTF), and Cardiotrophin-like Cytokine 1 (CLCF1). OSM is widely expressed *in vivo*, and it can be produced by a variety of immune cells, including T cells, monocytes/macrophages, and neutrophils.

The receptor complexes of the IL-6 receptor family all contain the GP130 subunit. OSM receptor complexes are heterodimers; based on the identity of the second subunit within the complex, they can be classified into two types: Type I and Type II. The Type I OSM receptor complex consists of the α-subunit GP130 and the β-subunit LIFRβ (LIF Receptor β-subunit), whereas the Type II OSM receptor complex consists of the α-subunit GP130 and the β-subunit OSMRβ (OSM Receptor β-subunit). When OSM and the two subunits of the OSM receptor complex are simultaneously present, OSM first forms a low-affinity heterodimer with GP130; this heterodimer subsequently recruits and binds to either OSMR or LIFR, thereby activating various signaling pathways, including the JAK/STAT, MAPK, JNK, and PI3K/AKT pathways.

The HEK293 Human OSMR Effector Reporter Cell Model—effectively simulates the signal transduction process of OSMR *in vivo*. The underlying principle is illustrated in the figure below.

Figure 1. Schematic Diagram of the HEK293 Human OSMR Effector Reporter Cell Model

Figure 2. Recombinant OSMR Effector Reporter Cell stably expressing OSMR.

Figure 3.Dose Response of Recombinant Human OSM in OSMR Effector Reporter Cell(C4).

Figure 4. Inhibition of rhOSM-induced Reporter Activity by OSMR Blocking Ab in OSMR Effector Reporter Cell (C4). Inhibition of rhOSM induced Reporter Activity in OSMR Effector Reporter Cell(C4).

Cell Resuscitation
1)Rapidly thaw the frozen cells in a 37 °C water bath for approximately 60 seconds. Once thawed (which may take slightly less or more than 60 seconds), immediately transfer the cell suspension from the cryovial into a 15 mL centrifuge tube containing 10 mL of pre-warmed  HEK293 Human OSMR Effector Reporter Cell complete culture medium.
2)Centrifuge cells at 1000 rpm for 5 min to remove medium, then resuspend cells in 5 mL of pre-warmed complete medium.
3)Transfer the cell suspension into a T25 culture flask and incubate at 37 °C with 5% CO₂.
4)After approximately 24–36 hours, replace the medium or passage the cells to remove non-adherent dead cells.

Subculturing procedure
1)When the cell density reaches the appropriate confluency for passaging, wash the cells with PBS, then add 1 mL trypsin to detach the cells. When more than 80% of the cells detach upon gently tapping the culture flask, add complete culture medium to terminate digestion. Gently pipette to obtain a single-cell suspension, transfer to a 15 mL centrifuge tube, and centrifuge at 1000 rpm for 5 minutes.

2)Discard supernatant after centrifugation. Resuspend cells in fresh medium to a single-cell suspension and transfer to a new culture flask for continued growth.

Cell Freezing
After trypsinization and centrifugation of cells from each T75 flask or 10 cm culture dish, discard the supernatant. Add 2 mL of cryopreservation medium (90% FBS + 10% DMSO), gently resuspend thoroughly, and aliquot into two cryovials. Immediately place the cryovials into a controlled-rate freezing container (e.g., Nalgene 5100-0001), fill with isopropanol to the indicated level, and store at −80 °C. After 24 hours, transfer the cryovials to liquid nitrogen for long-term storage.