The power companies try to reduce the power generation cost to satisfy the costumers and increase the profit. For this purpose, various acts including energy management strategies, power loss reduction plans, efficiency increasing of the gird components, etc. have been done in the past. Currently, the integration of natural gas and electricity networks for simultaneous operation is one of the most effective approach. In the integrated networks, the natural gas and electricity are managed simultaneously, making it more beneficial for both suppliers and customers. In this paper, the supplied and demanded natural gas and electricity are managed simultaneously to reach more benefits from both technical and economic perspectives. The studied integrated network includes power plants, gas supplier, gas storage, water electrolyzer, fuel cell units, wind energy and hydrogen vehicles. A comprehensive investigation is carried out to optimal energy management in a modern integrated energy systems, the hydrogen vehicles, as a new transportation vehicle, is included in the system. Both natural gas and electricity demands are supplied optimally using the proposed optimization algorithm. The demand response programs are considered as the flexible loads to increase the system profits. The optimal operation problem is modeled as a mixed integer linear programming problem and is optimized using GAMS programming software. The proposed methodology is simulated in various scenarios and its robustness and effectiveness are discussed.